Fixing Fiberglass on a Westy top


New member
My top came off in transit after we bought it. We had some major fixing to do, missing corner, front right busted in several areas and several cracks, not to mention the tent wood was mostly gone/smashed up.

My son (Joe) works on cars, mainly body work and paint so he was of great help doing this work. He’s highly certified in his trade, he surprises me with his knowledge, as a kid he seemed to not be motivated…then he discovered something he loved, fast cars, could make him a good living…he’s restoring his ’66 Cobra Jet Mustang right now. I documented our repair, will post some pics later, here it's very complete.

To repair missing areas we made a template mold of an area similar to the missing piece on an area near the busted out pieces from fiberglass with 2 layers of cloth (not chopped fiberglass but the cloth). See details below. Read and understand all the steps and I suggest you ghost rehearse this so you aren't stumbling around while time is critical on the resin curing time.

Calculate the cloth you need by comparing the layers to sizes cut out of a stock cloth purchase, it comes in bags from 3M or other sources.

You’ll need;
Sharp scissors, to cut the fiberglass cloth. Try to cut on the weave so you have minimum fraying, cut off the frays at the edges, DON’T PULL them or you’ll make a mess of your cut out cloth.

Several (minimum of 1), 2” or 3” disposable brushes for each time you use the resin (size depends on size of repair area, you want to cover quickly so choose the brush size appropriately.

Resin and hardener, it usually comes as a kit but buy another hardener tube as a backup.

You will need Nitrile Gloves (blue) so you can do this messy work without getting resin all over yourself.

To get started;

1. IMPORTANT: Set up the Westy top on a 2 saw horses, top up. (It helps if the sawhorses fit inside the tops sides). Identify an area on the Westy top that templates the area damaged/missing. and make sure it's in a similar position on the top to the repair area that way you are copying a like section of the top with the same shape and curves. Clean area to be copied of debris and other dirt, so it is very smooth but do not sand it except to remove bumps you can’t avoid! The object here is to start with as pristine area as possible as you are making a mold to copy. You are basically make a mold template/copy of a good area to be used as a mold to fix the damaged/missing area.

2. Then after cleaning, and drying (use heatgun to dry if wet, fiberglass and water don't like each other.) Next, put a coat of Carnuba wax on that area liberally but not where it shows any swirls...overlap area you are copying by 4" on a side with the wax. I always rub it in so any porosity of the existing top is saturated; the object is to create a wax layer so the resin won't stick to it while making your template.

3. Cut the fiberglass cloth so it overlaps the hole/missing piece by 3". (you want a 1" border outside the cloth with the wax applied). In step 5 below I cover how to do the resin/cloth layers. The 1" border is your space buffer so the new resin/glass doesn't stick to your template area.
It really helps to have a helper work the cloth while you do the resin, things go much quicker and it’s easier to concentrate on your task.

4. The key property of resin is that it is workable for around 10-15 minutes, the higher the ambient temperature it is the shorter the resin work time is-- 100F will give you 5-7 min. work time. The resin/hardener mix ratio is predetermined to be usually 1 drop hardener/oz of resin (read directions on resin can); you will also need a measuring cup, available at paint stores to get the right amount of ounces. For the process below you will use approximately 1oz. of resin for each square foot of 2 layers of fiberglass cloth. This will, of course, vary according to how much resin you use. A thin coat is not good as there is nothing left to soak into the cloth, I suggest a moderate coat of 1/16” or so though it’s hard to measure as a gel liquid. Mixing a bit more the first time may seem wasteful but if you don’t have enough to complete the job you just wasted all of it. After you do this one time you will have a good idea how much to use on the below fix job of 4 layers…

Suggest 3M resin, it is the most consistent, cures well and is very strong. It is available at Home Depot and Lowes…

Mixing the Resin and using it;

5. You have to work fairly quickly as the resin will begin to harden the instant you put in the hardener…stir quickly and begin your work. After mixing resin with hardener, using a 2"-3" throwaway paintbrush, put a medium thick coat of fiberglass resin over the selected replication area directly on top of the Carnuba waxed surface with the brush (pour some on to quicken the process if your area is larger), lay it on smoothly but DO NOT RUB IN the first resin layer, it will disturb the wax and stick to the Westy top, something you don’t want to do! Then add 1 sheet of your precut pieces of fiberglass cloth, flat over the resin, covering the entire area being worked. Brush it down coating it all and brush completely to remove bubbles and raised areas Note: The resin will run if the area is not flat, so be careful to not let it get on the un-waxed areas, I usually put a tape barrier at the perimeter with the tape down on 1" area and standing up toward the work area to block any runs. You can also apply the tape flat with a 1/2” raised area stuck to itself as a barrier.

Note: If at any time the resin starts to get lumps like Jello, stop immediately, as the resin has hit the time window for curing and proceeding with a hardening resin just makes a huge mess. It’s better to stop, let the surface resin cure for ½ hour, then mix up some more resin and finish the job.

6. To put on the second fiberglass layer, lay the cloth on top of the first layer’s resin top coat as quickly as possible. Add more resin on top, same as before, be sure it's smooth, again brush it in/on thoroughly to remove bubbles/raised areas. Here it helps to press down on the brush to make the fiberglass layers make good chemical/liquid contact.

If your fix area is more than 1 ft. in size I suggest adding third layer for extra strength just to be sure. This makes your template stiffer and easier to use later. The bottom of the glass/resin will take the form of the area you selected and be pretty smooth as it copies the shape of the top.

7. Let it harden 1 hour and then pop off template carefully by flexing it slightly so as to not damage it. Remember it’s still not fully cured but hardened enough to work with. If it gets out of shape you can use a heat gun to reactivate the resin so it's pliable, don’t overdo it or you will misshape it worse, then check to be sure it still fits the pattern area by pressing it on the area you originally made it on. Once the resin/fiberglass is done, set it aside, flat side down, for 24 hours in the shade. It will harden nicely. If there are any shape imperfections those will not be a huge factor as when you use the template it will be screwed down and take on the shape desired. (later steps)

If you have something like old 'roof window holes' that are side by side so it's likely this one template would work for fixing both, if not make another template for the second area following the same directions above.

Once the template is fully cured, you do the Carnuba wax again but it's applied to the inside, the side that was against the Westy top when you made it. Be very careful not to get any wax on the Westy top as it will stop adhesion of the new fiberglass resin/cloth to the repair area on the actual Westy top. You simply don't want resin sticking to your template copy, the wax prevents that.

Now for the repair work

Preparing the work area;

IMPORTANT: Caution, wear old clothes, cover skin well, use breathing filter and goggles that seal to your face and a hat/gloves while doing this grinding work. The Dust will get all over everything in sight…afterwards shower in cool water as warm/hot water will open your pores and cause the dust to be absorbed into your body!
(Another reason few people do this kind of work…)

...will continue in next post...


New member
Continued...Oh well this ended up on top of my first post in the below post first then continue here...sorry

8. While the template piece is hardening for 24 hours you can use that time to prepare the fix area, the first step is to clean up the rough edges on the top of the Westy top. You ‘must’ use rough sandpaper, 24-36 grit to rough up the Westy top material out to 3” beyond the hole size on the inside of the top and 1” from the hole edge on the top of the Westy top. On this 1” taper you want to slightly taper the edge down (working from the top of the Westy top). See note in step 10 on completing this by using this taper as a holder for resin to form fit it into the hole. The resin will form a sideways ‘V’ around the edge of the hole using this process, it’s very strong and connects top to bottom.

On the sanding, (Don’t overdo this, you can always sand more but you can’t put it back without problems! Using heavy grit sandpaper is very unforgiving but you need the big scratches in the composite Westy top material for the fiberglass resin to grab onto for a good bond.

Back to the sanding process…
This is critical as the original top isn’t really fiberglass but a composite material molded at the factory and has similar characteristics to fiberglass. The other thing that is important is this composite material has a ‘mold release agent’ left over on the surface when it is made; it is used to get the piece out of the factory master mold once it cures. If you don’t sand this material off the top, this mold release agent will prevent the resin you are adding from sticking. Your repair it will look good then pop off under the slightest stress, a bad thing, so you must grind down the surface to expose the internal composite (usually will appear as a lighter color when you sand it down). Also when sanding the ½” area on top of the Westy top, I take the sanding lightly back to 1” to remove paint. During this work I use a vacuum near my work to collect the major dust. I wouldn’t use a fan as it will make a huge mess down wind. The last thing you want is the mold release agent in a powder form lying all over your work area when you go to apply resin… Then I clean the area with water well prior to working the fix to remove all powder, again you must dry the area prior to proceeding with resin work.

9. Applying the template so you can make the fix;

Now you will use that flat template surface as a base for your new fiberglass fixes. It is critical the bottom side (side toward original top of Westy top) of your template be applied on the top of the Westy top over the hole to be repaired. That surface is the flat side and when you attach and flip over the Westy top to create your hole patch this template acts as a mold to fill with the repair resin/cloth to create the hole’s repair.

To apply the template I use 2” heavy masking tape to position it making sure my 3” border is consistent around the edge of the hole. Once the tape is on, I then use short 3/8” long #6 hex head sheet metal screws located 1” from the edge of your template piece screwed thru the template piece into the Westy top. (pilot drill 3/32” holes through your template piece and the Westy top to make this easier). Position the screws every 4” making sure corners have 1 each. The reason for hex head is that getting the screws in is difficult, you will have better luck with a hex head tool vs. a screwdriver. You will later take out the screws, taper the holes then fill them with resin to complete your repair. The screws are necessary to hold the template in place and make it as strong as the Westy top so when you do the repair you don’t have issues with the template moving/flexing while you do the hole fix.

10. Now you are going to lay 4 layers of resin/fiberglass just like before but you must work very quickly (and I mean quickly, seconds count!), and having all the fiberglass peices cut prior is a must! It also helps to have a helper to lay out the cloth so you can quickly work the resin. Now you mix up a new batch of resin but you will need about 6-8 oz’s this time depending on thickness of resin layers etc.

Remember in step 8 where we tapered the edge of the Westy top’s hole? Here is where that comes in handy. This is very important as when you apply the first resin coat you push some of it under the edge to the template where the top is tapered slightly so you get a clean edge fix not one you have to re-do later. Remember the template we made first, we are now looking at the bottom of it working the 4 layers from the inside of the Westy top. I use the edge of the paint brush and scrape it along the edge of the hole, as the resin comes off the brush you push it under the edge. This provides the final 4 layer a sideways ‘V’ bridge to both sides of the hole and makes it very strong. Do this quickly around the entire perimeter of the hole, don’t rub too aggressively as the wax will come off, just push the resin under the edge, then after putting resin on the entire surface of your template, apply cloth, repeat 4 times with a final resin coat on top of the 4 layers…smooth out, pour some remaining resin (not too much) to flatten out the work area. Brush to level it out. I must repeat, doing this 4 layer process is time critical; you need to work fast, admire your work after you are done! This is all going to be inside of the Westy top, you can sand it down to a finish state after it cures, suggest a 24 hour cure time.

Again - Note: If at any time the resin starts to get lumps like Jello, stop immediately, as the resin has hit the time window for curing and proceeding with a hardening resin trying to save it just makes a huge mess. It’s better to stop, let the surface resin cure for ½ hour, then mix up some more resin and finish the job, picking up where you left off. If the ambient temperature is too high 90F+ you may not have enough time to complete the 4 layers…better to stop and restart than make a huge mess. You can’t brush the resin Jello into the resin, don’t waste your time!

Important note for those that want to do 6 layers in one set because as we all know, “more is always better, right?”…Don’t do it!!

Using resin for 4 layers is the max you should do at one time as curing creates heat (an exothermic chemical reaction between resin/hardener) and more than 4 layers creates too much heat which delaminates the fiberglass cloth layers as it cures, it ruins your work. Also, from my experience doing this, using 4 layers also will replicate the Westy top's average thickness. Later, as a separate step, if you desire a perfectly level and clean inner Westy top surface you might need to put a bit more resin/cloth over the 4 layers to fill in any top pinholes or dips then sand down and finishing with 220 grit for a flush painting ready surface. This also applies to the top of the Westy top. That way when you paint the top, inside and out it looks like no one ever touched it, no flaws, flat flush fiberglass work…a good strong job. Speaking of the Westy top paint, I sanded off all of the original finish down to bare composite, then I primered, painted (twice), cleared (twice). It looks fantastic, better than new (using the same original color I copied from the luggage rack (also repainted it after sanding for paint to stick)!

Closing notes:

By the way, you can make template pieces the same way of any portion of the Westy top. I made one for a corner by using the other corner as a model, be sure to use the same portion, at least the Westy top curved corner is mirror imaged so this works well. I also made a piece to fix the end of the flat side as mine got 8-10 inches torn off in the accident, I just made a template of the side 1’ down the top, then when I went to fix the bad corner I just slid my template to overlap the corner, waxed it, screwed it down, then built up the corner over the template as it hung off the end, trimmed the overage and viola, fixed.

I’ll post some pictures later of our work, I have a 1969 Westy that we are refurbishing…the top is the first part, I’m replacing most everything that is ‘old/worn out’ and anything that is broken…including making my own stronger scissor brackets for the top, a $400 tent, the $80 cot, all the wood inside and upholstery/curtains/carpet/seat covers etc.

Hopefully this write up will help others willing to take on this task. If you can find a fiberglass person to help, all the better but don’t be surprised if they have different ideas on how to do this. These steps work, and as I’ve noticed everyone has their own methodologies…in fact my son wanted to do all 4 layers himself (he didn’t have time to do 2 on the first template due to shuffling tasks along the way, but with my help working the glass as he worked the resin we finished in around ½ the time so we used the extra resin left to fix a few more spots…

Best of luck, hope this helps. If you have any questions, post them here and I’ll check back to see if I can answer any of them.

Tully Mars

New member
Excellent post. Thank you. The 3M product you identified is a polyester resin. What are your thoughts on epoxy resin versus polyester for this type of repair? Also, you apparently did not put a gelcoat on. The original construction does not have a layer of gelcoat? Correct?
My understanding is that polyester epoxy must be sealed to fully cure. So, did the paint serve this purpose? And lastly, my 84 Westfalia top with the issues has somewhat of a texture. Did you have a texture on yours and how did you "match" it? With the primer/paint process?