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Tips for Cutting Fiberglass?

Home Forums General Discussion Tips for Cutting Fiberglass?

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  • #306597
    Mark Radzin
    Participant

    @marco_lardo

    Hi all–

    Relatively new here. I had been shopping for an MGTD kit car, but the rather draconian DMV laws in Connecticut make it exceedingly difficult to register a kit car from out of state, but incredibly easy to do so for one previously registered or titled here. Well, lo and behold a Bugatti type 35 kit came up at a price I couldn’t pass up, so… I didn’t pass it up. I love the TD, but it looks like that will have to be my next one!

    Anyway, unlike many of these kits, it does NOT have a hatch built into the hood to access anything in front of the cockpit. For many reasons I need to put one in, and I have studied the car well and have a plan in place in terms of what specific work needs to be done to realize it.

    My big concern is that I don’t have any experience cutting this kind of fiberglass, and there doesn’t seem to be much info floating around out there specific to kit cars of this era. Does anyone here have experience cutting body panels on these? What are the pitfalls? What tools/blades work best? Any information anyone could provide would be much appreciated!

    Thanks much and stay safe!

    • This topic was modified 5 months, 2 weeks ago by Mark Radzin.
    #306599
    R.Putnam
    Participant

    @rickputnam

    Marco, I have had good luck with an air powered 3″ cut off tool. be careful, it cuts really fast, but very clean. wear eye protection and a dust mast (if you can find one). with a steady hand it cuts fairly straight, but again very fast. A 90degree die grinder with a 2″ disk works well to profect your work, but hand sanding with a block is much safer and cleaner. Good luck, and we would really like to see that Bugatti replica.

    #306600
    Mark Radzin
    Participant

    @marco_lardo

    Thanks for the tips— I  need an extremely straight cut for this, so was thinking of using the Dremel Ultra Saw, which is a small and fine bladed saw that has built in guides that I can use with a jig to keep the cut straight.

    in addition to taping the area to cut to avoid chipping and marking the line on that, I thought it would make sense to put hash marks across the cut line to facilitate proper alignment when I reinstall the hood piece.

    in terms of finishing, I understand the edge needs to be sanded, but is there also a need to seal it? I was thinking to spread a layer of epoxy along the edge to avoid any future delamination or flaking.

    Thanks again for the help— any other advice is greatly appreciated! Will make sure to post a few pics of the Bug-atti when I get a chance.

    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    #306604
    secretagentcat
    Participant

    @secretagentcat

    Just a safety reminder…

    Have a fire extinguisher handy. Fiberglass is VERY prone to catch fire and when it does, it burns fast! you never know what your blade might touch and set off some sparks that might catch fire. It’s always better to be safe than sorry…

    I almost bought the kit you’re talking about. They’re beautiful cars and the one I looked at had a front hood that was hinged and opened on both sides! The Volkswagon was accessed in the rear by lifting the back trunk that was also hinged! It was soooo Cool! It wouldn’t start, when I wanted to test drive it so the dealer told me that they would fix the problem (a starter relay switch) and I’d return to test drive it in a couple days…When I returned, in a couple days, the car was sold! I was broken hearted but a month later, they had my MG kit car on the lot and I bought it. I’ve loved her ever since!

    I’d also love to see some pictures of your ride!!!

    #306605
    Michael Davis
    Participant

    @oldnslow

    If you are cutting from the “good” side, use a jig saw with a very fine blade, but one that cuts on the down stroke, not the up stroke. The teeth point down. These are available at hobby supply stores and woodworking sites. They are fairly easy to find. Plus use tape to protect the surface.

    #306606
    Mark Radzin
    Participant

    @marco_lardo

    I appreciate the additional advice. Just how concerned should I be about fire? I have seen people cut fiberglass with small circular saws like the one I plan to use (as well as multi-tools like the Fein Multimaster). If I keep a good feed speed, should fire be something I fear or just be mindful of and ready to deal with if things somehow go south?

    At any rate, I think I need to use the small circular saw at least selectively. Even if I have to use a jigsaw for the main cuts, I at least need to do an initial plunge cut to get started. Also, there are a few select places where there is material I need to not cut fairly close behind the body panel and that a jigsaw would impact. One of the things that attracted me to the Ultra Saw was that it has precise control over cut depth and maxes out at 3/4”, which could be vital in those spots.

    So hoping the Ultra Saw works as described, but if not I can fall back on my jigsaw for all but a few cuts.

    Thanks again!

    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    • This reply was modified 5 months, 1 week ago by Mark Radzin.
    #306611
    secretagentcat
    Participant

    @secretagentcat

    Just be mindful of the fire hazard. I was watching an episode of Fast and Loud, when one of their fiberglass projects caught fire. They had to rush to put it out quick. I think they were working on that Vet they did for Hot Wheels!

    And the idea of the Tape is brilliant! that helps to reduce the chipping on the topside of the project. And what ever tool you choose to use, always use a fine blade and buy a few since they dull fast, while cutting fiberglass…

    #306615
    Mark Radzin
    Participant

    @marco_lardo

    I should do a proper post on this li’l jalopy, but since you’ve been so kind in sharing your expertise, here are a few pics per your requests!

    #306616
    Mark Radzin
    Participant

    @marco_lardo

    Another…

    #306617
    Mark Radzin
    Participant

    @marco_lardo

    And just one more…

    #306618
    secretagentcat
    Participant

    @secretagentcat

    She’s a Real Beauty!!!

    The one I looked at and tried to buy had racing screens rather than a proper windshield. This way, you’re avoiding the mandatory racing goggles! LOL

    I sure like it!!!

    #306619
    Mark Radzin
    Participant

    @marco_lardo

    Thanks! I actually would prefer the Brooklands style screen, but it came with this one. I believe the racing screens were not street legal in CT when this was registered (nor are they now). So full windshield it is. While the Brooklands would be more authentic, there were some contemporary Bugattis with similar windscreens, so it’s not entirely without precedent. And as you say, it provides a bit more anti-bug protection!

    Who knows, if I ever move somewhere with less stringent regulations, I may well change it out.

    BTW, what color was the one you had wanted before the MG came your way?

    #306620
    secretagentcat
    Participant

    @secretagentcat

    She was Beautiful! Yellow paint with Black leather interior! The engine was a supped up VW 1776 with dual carbs! the entire front end was storage and when you opened the Boot, it was black carpet with mirrors showing off the 6 disk CD changer and the security system! She was amazing!!! I had always hoped to see her driving around Redlands or Yucaipa but I never saw her again…

    She was The One That Got Away!!! LOL

    But don’t tell The Penny Marie I said that!!!

    #306621
    edward ericson
    Participant

    @edsnova

    You shouldn’t have to seal the cut edge of the glass but an epoxy coat is probably best practice and suitable for marine use. You will want to finish the edge with paint and that should prevent delamination for many years in this application.

    Using a jig is also the right idea. I free-cut a fair amount on Bridget and found there’s no way to make a perfect straight line without jigging it up.

    Aside from the cutoff wheel on a grinder, and the jigsaw and the small circular saw, best tools are a Dremel and/or a drywall cutter (i.e. Rotozip, etc.).

    There is no way to do this without making a lot of dust. It won’t probably catch on fire but your skin might feel like it did!

    Congrats on your Bugatti and welcome to the group!

    #306647
    Paul Mossberg
    Keymaster

    @pmossberg

    I cut a lot of fiberglass with a jig saw. I used blades that had no teeth, but have a abrasive “grit” cutting edge. Look for blades intended for tile, stone or masonry.

    If you’re trimming, it;s best to cut “large” and sand down to your marks.

    For the job you are doing, a long straight cut, you’ll want some sort of jig set up.

    Most kits were manufactured with chopper gun fiberglass, not hand laid sheets. There should be no need to “seal” the edge other than paint.

    Wear eye goggles and a face mask. You don’t need a respirator as you would for paint of fiberglass layup. But you don’t want to be breathing in the fiberglass dust.

    Wear long sleeves, long pants and gloves. Don’t ask why I know that!

    Paul Mossberg
    Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
    2005 Intermeccanica Roadster

    If you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)

    #307032
    Mark Radzin
    Participant

    @marco_lardo

    I am about at the point of doing this cutting project and talked to a guy in a body shop to pick his brain, but he does not seem to know a lot about these kinds of cars or this kind of fiberglass. I am going to do the job myself, but some of the things he said brought up questions that you all surely jame more expertise on:

    — He seems to think it would be necessary to build an attach a frame to back of the hood to keep it from warping. I don’t recall seeing that on any other fiberglass kit cars, and would think that if I have the piano hinge at the top and a flap behind all the edges with 3 strong hold downs at the bottom, that warping wouldn’t normally be a problem.

    — Also, he was of the opinion that the whole car would need to be repainted No matter what, but from your previous replies it seems like taping the cut and using a very fine grinding blade for tile or metal would help avoid chipping, and that sanding and painting the edge (I may do epoxy under the paint as well) should probably— PROBABLY— be fine. In terms of minor touch ups, I have found a readily available paint shade that is a near PERFECT match for my car’s finish color… so minor touch ups along the edge are a possibility.

    So, in the opinion of those who have experience with this kind of cutting, and experience with hoods (!), am I right or wrong? The main thing is I want to get this work done and look good, but don’t want to spend an arm and a leg or take the car to pieces to do it.

    #307035
    edward ericson
    Participant

    @edsnova

    You’re right, re the paint. The more care you take the better it’ll end up looking.

    Regarding the hood reinforcement, it depends on the hood. On the TDrs, some of them are a bit floppy, with no reinforcement. Some are floppy with wood spars glassed in underneath. Mine is a little floppy with a metal trim piece bolted through the middle, and some thin metal reinforcement glassed in on the hinge side.

    I’ve yet to see one that’s really stiff and sound. Maybe on the Allison cars?

    They don’t really “warp” though, once cured. And believe me, after all the time that’s passed since these bits came out of their molds, replica TDs and Bugattis are fully cured.

    #307038
    Mark Radzin
    Participant

    @marco_lardo

    Thanks, Edward. Very helpful.

    Do you think it would make sense to add a little bracing in the back? If so, what would be the best way to do that?

    #307039
    Dale Schumacher
    Participant

    @schu

    I installed two oak 1×1’s full length on either side of the center and used fiberglass mat and epoxied them to the bottom of the hood on mine many years ago. Really helped stiffen up the hood and still doing great.

    #307046
    Mark Radzin
    Participant

    @marco_lardo

    Thanks, Dale! That is helpful. Do you think some metal bar stock applied the same way would do? Seems like it would provide similar rigidity with a lower profile.

    #307047
    Dale Schumacher
    Participant

    @schu

    I am sure it would – maybe 3/4″ square aluminum – light and rigid. Can buy at Lowes or Home Depot in the hardware dept.

    Bar stock might flex down ( sag ) a bit – not rigid like square or triangle stock in my opinion.

    #307099
    Mark Radzin
    Participant

    @marco_lardo

    OK— I made most of the cuts, and the hood is now detached. I still need to remove the lip at the front of the hood that attaches to the “radiator” (it will be replaced with a new lip the hood rests on) and the central cut down the hood I still need to sand down on each side to account for the thickness of the piano hinge. But the worst is behind me, and the two critical cuts at the rear and bottom cane out darn near perfectly. So thanks to everyone for the advice, I’d have been lost without it.

    So now I have a new (and partially related) issue that I’d like to run by all of you… it touches on other things with the car, but no need to do a whole new thread:

    My gas tank needs work. It had rusted inside, and my VW guy flushed it but it can’t be driven much at all without getting this fixed. The current tank is a tapered box that fits perfectly in its spot (lower right side). My mechanic would ideally like to remove, reline, and reinstall the tank. The problem is that it was installed before the body was put on and there’s no easy way to get it out. So it seems like I have three possible options:

    A: Decommission the existing tank and install a new one. This would require venting the old tank (I would probably cut a hatch in it and use it for ballast). The downside to this is that there is t a great place to put a new tank— it would have to ride high and would be difficult to secure. Also not that important but a consideration is that it would kill any “trunk” space I might have in there (I was hoping to put a shelf on the frame above the gas tank and other mechanicals).

    B: I could remove the entire front of the body and slide the tank out the way it came. This would obviously be “best practice” but would be a staggering amount of work, may carry with it unforeseen problems, and given how this car was assembled in the first place I am concerned whether it would be possible to put it back together properly.

    C: This option I need advice as to whether it would work… I will post pictures when possible to help visualize it. After cutting the hood, I am left with a strip of body at the lower portion of the passenger side approximately 4 feet long by 10” high. I could Cut the strip behind the gas tank and remove it in the same way I would if I took the whole body off— only I would have just three bolts to undo. After re-installation, my plan would be to rejoin it and touch up the paint to match (I have a commercially available spray paint hat is a near-perfect match to the body color). I could also disguise the join line: Of the 10” to be cut, 3” is curving away under the car, 4” could be placed between two false louvers, and the upper 3” could be placed behind the rearmost hood hold down. If it could be joined, I think it could be well camouflaged and wouldn’t be too noticeable (the car already has quite a bit of “character”.

    So I have two questions: First, which seems like the best solution? Second, if I were to do Option C, what would be the best way to rejoin the two pieces and fill the cut line (about 1/8” thick)?

    As always, your expertise and advice is greatly valued.

    #307102
    Mark Radzin
    Participant

    @marco_lardo

    #307103
    Dale Schumacher
    Participant

    @schu

    Just a thought:

    I use a product called Metal Rescue to remove the rust out of my motorcycle tanks – it is like water and can put your hands in it without hurting your hands or paint. I leave it for a few hours and cleans like crazy.  I pour out the product when clean and save it for a few other tanks. I flush out tank with water and and spray inside of the tank with WD40 so it does not rust flash. I understand this is different and on a larger scale – I think there is a concentrated version of the MR and you add water to fill your tank so it will clean the whole tank. You could just pump out and strain and reuse till clean. If the rust is really bad it would be difficult sucking out the trash but might be doable. Google the product and take a look. If you have a big opening on the bottom it might be easier flushing out the bottom and catching the product and straining out the rust etc. You can reuse the MR up to a point.

    #307104
    Mark Radzin
    Participant

    @marco_lardo

    Image above is immediately after hood removal (there are still a few acorns and such a squirrel left there many years ago!).

    If I did the cut for option C, it would be straight up and down directly under the rearmost hood hold down, making sure to go at the point directly between two false louvers.

    Another benefit of going behind the hold down is that the two screws that will mount the lower portion of the hold down to the car would also go on either side of the cut, so the hold down bracket would bridge and stabilize the cut (obviously I will be building out a plywood wall where the hood overlaps the cockpit).

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