building up corner of fender for truflex bumper
03-29-2007, 09:49 AM
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building up corner of fender for truflex bumper
Hoping someone can offer some advice. I am doing the initial prep work before painting my car later this summer. I have a truflex front bumper but the driver side corner does not fit flush. I need to build up this front corner of the fender. My plan is to use epoxy resin and mat to build up, It needs to be built up a total of 1/2 inch. Now the dilemma, the front fender is SMC, the front surround is straight fiberglass. Can I use the epoxy resin for both ? or would you just build up layers of evercoat filler to build it up. I think the resin and mat is the way to go for a solid repair, but I know you are supposed to use different resin for fiberglass and SMC and the repair is going to be over both.
03-29-2007, 02:44 PM
#2
Drifting
I would like to see pics before offering advice to play it safe, but according to your description you have gaps on one or both ends of the bumper to the fender. Do you have gaps across the hood surround?
You should always make your modifications to the bumper, instead of the body. Making mods to the body is permanent, bumpers are replaceable so make you mods to the bumper. However, I don't recommend using filler on flex fiberglass bumpers, but as long as you don't stress the filler during final assembly, you should be okay. Standard fiberglass is my choice since both types usually require filler for a perfect fit. Also, make sure that none of the inner structure or absorber is interfering with the fit. The bumper cover should not touch anything behind it that will interfere with fit or cause a rub point.
I've found that 99% of the front bumper fitment problems will be on the ends and having up to a 1/4" gap between the end of the fender and the edge of the bumper is quite normal. But before you resort to filler, you need to make sure you have a good fit across the front of the hood surround without pressure. You have a '74 so the fit should be relatively easy and straightforward, but if the gap is no consistent, the top mounting surface (back side) needs to sanded to match the body contour across the front before filling the ends. The gel coat is pretty thick and a lot of fitment problems on the ends can be minimized or solved in this step. Use a flat block and stop sanding when you reach the fiberglass.
2. Once you have the best fit across the top you can concentrate on the ends.
Use "Evercoat Vette Fill" to fill the end gaps essentially making a mold on the back of the bumper. No filler is needed on the body at all, in fact there will be no damage to your paint. This method also insures that the body and bumper mounting surfaces match at the same angle. I'm not referring to the visible outside gap, but the gap inside where the bumper and body tighten together. If you were to do a cosmetic fill on the outside, then tighten the bumper to the body and close the inside gap between the 2 surfaces, the top or side surface of the bumper will distort from the pressure. It may not happen right away, but within a couple months you could have a crease in the surface.
This process works better the first time with a helper. To fill the gap (assuming the top fits perfectly without force) cover the front surface of the body and the mounting surface where the filler is needed (and slightly beyond) with Saran Wrap. This will keep the filler from adhering to the body and protect the paint. Sand the gel coat off the bumper where the filler is needed and slightly beyond as well as the some of the outer surface where the filler will be feathered. Clean the bumper with wax and grease remover. Vette Fill is thin so you need to work fast but carefull. Apply Vette Fill to the bumper mounting surface (one side at a time) and put the bumper in place against the body with very little pressure against the body. Use masking tape to hold the bumper in place and remove the excess filler that has oozed with a bondo spreader. Let the first coat dry.
Working on the same spot, force filler into the gap from the backside and remove the excess. You'll need to verify the gap between the fender and the bumper is filled sufficiently, add filler to air pockets if needed. Now just finish sand and feather the outer portion. The gap problem is fixed and when you tighten the bumper to the body, there will not be any surface distortion. Hope this helps.
You should always make your modifications to the bumper, instead of the body. Making mods to the body is permanent, bumpers are replaceable so make you mods to the bumper. However, I don't recommend using filler on flex fiberglass bumpers, but as long as you don't stress the filler during final assembly, you should be okay. Standard fiberglass is my choice since both types usually require filler for a perfect fit. Also, make sure that none of the inner structure or absorber is interfering with the fit. The bumper cover should not touch anything behind it that will interfere with fit or cause a rub point.
I've found that 99% of the front bumper fitment problems will be on the ends and having up to a 1/4" gap between the end of the fender and the edge of the bumper is quite normal. But before you resort to filler, you need to make sure you have a good fit across the front of the hood surround without pressure. You have a '74 so the fit should be relatively easy and straightforward, but if the gap is no consistent, the top mounting surface (back side) needs to sanded to match the body contour across the front before filling the ends. The gel coat is pretty thick and a lot of fitment problems on the ends can be minimized or solved in this step. Use a flat block and stop sanding when you reach the fiberglass.
2. Once you have the best fit across the top you can concentrate on the ends.
Use "Evercoat Vette Fill" to fill the end gaps essentially making a mold on the back of the bumper. No filler is needed on the body at all, in fact there will be no damage to your paint. This method also insures that the body and bumper mounting surfaces match at the same angle. I'm not referring to the visible outside gap, but the gap inside where the bumper and body tighten together. If you were to do a cosmetic fill on the outside, then tighten the bumper to the body and close the inside gap between the 2 surfaces, the top or side surface of the bumper will distort from the pressure. It may not happen right away, but within a couple months you could have a crease in the surface.
This process works better the first time with a helper. To fill the gap (assuming the top fits perfectly without force) cover the front surface of the body and the mounting surface where the filler is needed (and slightly beyond) with Saran Wrap. This will keep the filler from adhering to the body and protect the paint. Sand the gel coat off the bumper where the filler is needed and slightly beyond as well as the some of the outer surface where the filler will be feathered. Clean the bumper with wax and grease remover. Vette Fill is thin so you need to work fast but carefull. Apply Vette Fill to the bumper mounting surface (one side at a time) and put the bumper in place against the body with very little pressure against the body. Use masking tape to hold the bumper in place and remove the excess filler that has oozed with a bondo spreader. Let the first coat dry.
Working on the same spot, force filler into the gap from the backside and remove the excess. You'll need to verify the gap between the fender and the bumper is filled sufficiently, add filler to air pockets if needed. Now just finish sand and feather the outer portion. The gap problem is fixed and when you tighten the bumper to the body, there will not be any surface distortion. Hope this helps.
03-29-2007, 07:29 PM
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Thanks for your reply AL, I really like the idea of molding the bumper instead of the fender. I included a picture below, I do not have any gaps on the front surround or the passenger side, only the drivers side.
1/2 inch gap on the top corner which you can see in the picture and on the side of the fender also. I do have the 1/8 inch gap on the outside of both fenders as you described as normal. I do have the vette filler I already purchased. So after looking at the picture would you still recommend using that and using the saran wrap as you described. Or resin and mat on the bumper. Sorry wish the picture was better
1/2 inch gap on the top corner which you can see in the picture and on the side of the fender also. I do have the 1/8 inch gap on the outside of both fenders as you described as normal. I do have the vette filler I already purchased. So after looking at the picture would you still recommend using that and using the saran wrap as you described. Or resin and mat on the bumper. Sorry wish the picture was better
03-29-2007, 08:35 PM
#4
Drifting
It might be the picture quality, but the front edge of the body does not appear to be straight from the left to the right in the photo. It looks like there is a gap and a high spot where I drew on your photo? Also, it looks like the front of the fender has the wrong shape. Tell me I'm wrong and it's a bad pic
. I attached an overhead view of a '75 to show what the body and fender shape should look like for comparison.
If it's just a bad pic, yes, I would go ahead and fill the backside of the bumper, but if the front edge of the body is not straight and it appears that someone did some repairs in another life especially to the front of the fender, then you need to do some body work before fitting the bumper. Keep us posted.
. I attached an overhead view of a '75 to show what the body and fender shape should look like for comparison.If it's just a bad pic, yes, I would go ahead and fill the backside of the bumper, but if the front edge of the body is not straight and it appears that someone did some repairs in another life especially to the front of the fender, then you need to do some body work before fitting the bumper. Keep us posted.
03-29-2007, 10:36 PM
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You are correct, The front fender has has work in a previous life before I owned the car. I think the high spot you pointed out is picture quality because the front surround seems very flush. Actually the bumper is not attached to the car, I just held it up to the car and took the picture to show the gap in the corner to the right where you drew the arrows. The drivers side fender seems pushed back 1/4 to 1/2 inch compared to the passenger side which the bumper fits very good. but the door gap looks great on drivers side and beside a small crease repair on the fender "probably the root of the problem" which I have sanded out the old filler to repair it is in very good shape. Again thanks for your patience because I think you are sending me in the right direction.
