I'm looking to address some of the body work issues this winter and looking for other options in terms of repair. In 2003-4 when I shaved/molded everything, I used polyester resin/matte and I'm not too keen on leaving it that way for the new paint/etc . I was planning on removing all the 'work' I did years ago and use the West Epoxy system as the resin/filler/matte. Considering I'm in Michigan (freeze/thaw/heat) cycles and having purchased new front/rear bumpers in 2002 for the molding, I'm hoping to avoid any movement in the 'seam' areas. Any suggestions would be appreciated as this will be my winter project and hopefully repainted in early spring.

 

Look in the Paint/Body section in the General Corvette Topics tab, there are several tutorials there on molding in the bumpers and the various methods used including some that have used the West Systems epoxy. I've been researching there for my eventual dive into bodywork.

 

The beauty of the West Systems is they have hand pumps for each container, Parts A & B. Different hardners for different temps and you don't usually have to measure. The pumps are calibrated for the size container. One pump of A with one pump of B. SO simple even I could do it.

 

Yeah, 1 reason why I want to use it. I've worked with it before, just need to make sure it will bond with the vette glass/etc.... researching threads now

 

I used the West system for some structural repairs on my rear body mounts. I have a 79 corvette (SMC). The West epoxy is a mechanical bond and the surface must be prepped with a good sanding before you start. I used 80 grit and after it set, I sanded, shaped, and sanded some more. It seemed very solid to me.

One word about epoxy. If you plan on using random weave mat on your repair, epoxy will not dissolve the adhesive used to keep the strands in place. I haven't used random weave since all my repairs were in non-visible areas, so I cannot speak to how well the two mix. West sells some additives such as a colloidal silica thickener (406), a low density filler (407), and a microlight fairing filler (410). The technician I spoke with said you could use the light fillers as a skim coat over the repair to help prevent repair mapping associated with the oriented weave mat. I haven't tried that either, just passing along what I was told.

Overall I was very pleased with the West system and found that it adhered very well to SMC.

MajD

 

I have a 77, with mostly SMC, and I used West Systems exclusively. It is readily available here (I live in Florida, near the water), and I have used it for body repairs and mods, including molding in flexiglass bumpers and adjusting my door seams. It cures well and seems very stable. I also use it for filler, including pinholes, by mixing in their #410 Fairing filler and mixing it with the activated mixture until it is the consistency of peanut butter. It sands beautifully, leaving no edges.

 

FOR WHAT IT IS WORTH:

I am not getting into the debate if you should or should not. There are certain repair procedures that when the bumpers can be removed makes servicing things easier. So that is all up to you. Have I had to work on cars with molded in front and rear bumpers.. YES I have and I got the service work done but it cost the owner a lot more money due to not being able to remove these parts when needed.


When molding in front and rear bumpers this task can be a challenge. I do not care what you use or what you apply on the visible seam area you are trying to hide.. You still can run into issues due to the bumpers are not the same and the body. often times they may be made rather cheaply and are thin....thus ..they are more susceptible to moving than the rigid body GM made for your car.

Using an epoxy adhesive to bond the bumper to the body is do-able but the 'trick' is prepping the bumper and body so when you go to fill over the seam after you have ground out as much of the adhesive you used to bond the bumper to the body with. You actually now have an area you can fill back it and transition out from that seam.

Be aware that trying to keep that area above the seam THIN is not wise due to what may seem to feel fine and look fine can begin to show signs of distortion due to you did not apply enough material on that seam to provide it the needed strength to stop any distortion. SO this means your body filler will extend far out past that seam on both the front and rear bumper to hide the build up you need. And that is still no guarantee that it will pass all type of temperature changes. Which is why using an infrared heat source of some type to heat up your repair are within the limits of the products you choose to use is wise so that variable is taken out of the equation.

So for example. If a person is doing this and the air temperatures are at 60 degrees Fahrenheit. Then when the car goes outside in the summer when the surface temperatures can get to over 100 degrees Fahrenheit...they should not be wondering WHY they have a problem. Because a car stuck in a garage for 6 months due to it being winter is NOT curing as fully as many may think.

DUB

 

DUB,
When I molded in the bumpers years ago, I tapered both the bumper and body for glass/resin inlay in hopes to transition them better. As of today, you can see some ghosting, but I think it was due to possibly the poly resin and my technique at the time. I do have 2 IR heaters that I plan on using during these repairs to help in the curing process. I also plan on using a stock color this time, opposed to a custom mix like what I have now, so I can touch up/etc if anything happens.

 

Dub,
All of what you say is quite true. I started by thoroughly researching the matter of bonding in the bumpers. This is why I used True Flex bumpers and West Systems epoxy. After thoroughly prepping both bumper flanges, I bonded then with a mixture of epoxy and short strand fiberglass. This left enough cure time for me position the pieces and bolt the 2 flanges together with the stock retainers. After curing in the Florida sun and 80+ degree weather for a month, I proceeded to rework the outside using standard fiberglass techniques. This was almost 5 years ago, and I cannot see signs of the work (though I painted the car avorio - Alfa Romeo ivory - and the light color may tend to hide small visual problems). Ditto the third brake light I inset into the 7/16 inch flat area of the sugar scoop above the rear window and the reworked door seams.

 

The issue in what you did 'Rotonda' is you let the repair sit for a month in hot sun. Which I can assume can get quite hot down there like it can here in Charlotte NC.

Most people will not wait that long and want it done ...which can cause for problems in the future.

I know this process can be done and will work with no ghost lines...Simply because I have done it...but it is a process that I have chosen not to do, due to I just cannot live with any problem. Regardless if the owner can see it or not. If I see it, it bothers me and I just cannot live with defective workmanship in a repair. And to be honest the amount of time I would need would make this type of repair rather expensive for the owner which is another reason I choose not to do it unless they want to spend a lot of money for this conversion.

So for those reading this and want to do it ...go for it. I hope you take the time and use what is needed to make sure if you are looking for a modification that has no problems in it in the future. You applied those products and practices to achieve what you are ultimately looking for.

DUB