Wheel size? & Glass fender question

[john]

Hey


This is my first question after gleeming info off this site for around a year now. I couldn't ask for more from a site.

My first and more important question for me (I have a limited fiberglas knowledge) has to do with a couple of fenders I got off E-bay. They were $100 with $50 shipping. I was happy the fenders untill I first layed eyes on them. They had been shaped to fit something other than a 2d plane. (see link). They are not flat like the side of my trailer. Only about 30% of the back side lip runs flush with the side of my tear. The other 70% has been cut away.

http://pg.photos.yahoo.com/ph/johngwalk ... pg&.src=ph

I am sure it can be filled in, but some pointers would be helpful.

The second question has to do with wheel and tire size. Would you simply increase tire size or would you increase wheel size to fill out a fender? I don't mind a bunch of rubber. What size or sizes would you go to? As a point of reference the wheel in the pic is 14" with a 205/75/14 tire on it. See pic here:

http://pg.photos.yahoo.com/ph/johngwalk ... pg&.src=ph


Thanks in advance.

john

[doug hodder]

for filling the wheel well opening...I just took the fender over to Big O and told them to give me a wheel and tire that will fill the opening...also gave them the bolt pattern dimensions...A taller profile 15 might do it....as far as a class in glass body work...that one might be a challenge for someone other than a body shop, or body shop experience...I rebuilt a pair of Kit fenders on my 49 years ago, it was a real learning experience for me and they never looked too good...I've learned lots since then...for grins go by a body shop and ask them what could be done...get as much info as you can, then think whether or not you want to do the work...get a price while you're there...I would think that you are going to have to put in some sort of a flange along the mounting side, cut to the profile of the fender, the flange will need to be glassed full length..bolt the fender down with your flange to a piece of plywood that is covered with plastic like a heavy trash bag...that will keep you from gluing your fender to the plywood and give you a flat finished surface....then lay a patch of glass cloth on the backside, to fill the hole...after it cures, fill the top side with chopped glass and epoxy...grind and sand as necessary, repeat until it looks the way you want.....let cool until ready to serve...top with whipped cream...serves 8

Doug

[SteveH]

John,

I agree with Doug, the fiberglass work will be the most challenging.

Your fenders look like stock replacements for a '33-'34 Ford.

If I were to tackle the glass job, I'd build a wood mold that could be taped to the fenders that would have the same curve as the fenders with a lip attached. It could be very simple and even made out of cardboard because you are only going to use it once. You could use a release agent, or simply do like Doug said and put plastic on it. If you use plastic, put a release agent on the plastic also as it may be tuff to get off the epoxy also.

After the mold is made, the glass work is pretty easy, just keep putting glass cloth and resin on until it is as thick as the original glass. After you remove it from the mold, you will still have to use some filler like bondo to make shure the surface is smooth before you paint.

[john]

I am very familar with bondo but had not thought of useing it here. Ok so I can build up the fender with glass and then use bondo on what will surely be a poor glass job. Will the bondo adhere to the fiberglass ok? Is bondo regularly used on fiberglass?


john

[doug hodder]

You're going to want to most of your build up using glass cloth or chopped...that's where you are going to get your strength...only use the bondo at the end to fill in any low spots that aren't too deep...there's no strength in bondo....it's just to fill...and yes bondo is used on fiberglass all the time...but you should have the profile pretty much done in glass so that a light coat of bondo is all you need....what do you think Steve? .Doug

[SteveH]

Yes, just use the Bondo on the top surface to fill any irregularities in the glass. Bondo is regularly used on fiberglass and is actually made with the same resin as most fiberglass, polyester resin...it just has a filler in it to make it like a putty. If you use epoxy resin, just make shure you ruff up any edges of the existing glass so it adhears well, and also ruff up the top surface before applying the Bondo.

Earlier I mentioned using a release agent. That can be nothing more than a thick coat of automotive paste wax. Or, you can buy the commercial stuff that is painted on.

Again, the hardest part will be making the mold. I'm not shure, but I think you can get by with only one mold as the '34 Ford fenders are round in that area.

[purplepickup]

John, I have to modify my fenders in a very similar way that you do. I chose to use '39 Chevy fenders that don't have flat a flange on them either. Doug and Steve are right on the money with what you have to do.

In my case, I'm measuring very carefully and making a cut right where I want the flange to be. This cut will be a straight cut to match the flat edge of the trailer. Then I'm going to make a fixture to hold the fender in the correct position in relation to the future flange (the cut edge). The edge will be laying flat on a piece of ABS plastic I have, laying on the floor. The ABS plastic works good to mold against because it gives me a smooth surface and the resin doesn't stick to it. Most any kind of plastic with car wax on it, as a release agent, will work. Then I'll begin laying layers of cloth and resin up against the plastic base and onto the inside surface of the fender. I'll make the flange larger than necessary and trim it to size after it cures.

I don't expect much bondo will be necessary since the flange will form to the top surface of the fender making a nice clean corner, after a little careful cleanup.

Good luck and remember to measure twice (or 3 times) and cut once.

Right now I'm just making a pattern for my sides and mocking up where the fenders will be, but heres some pics of what I'll be dealing with.

Here I'm just mocking the fender location so I'll know what shape to make the side in that area.


This is what the edge looks like right now.


That white line is tentatively where the cut (flange) will be.

[angib]

Plan B, that is ten times less work, is to trim the fenders to give a straight 2D edge. This will make the fenders only as wide as their narrowest point now, but would only take an hour or so to do and would look perfect.

To do it, first cover the the first couple of inches of fender with masking tape. Then set up the fenders (similar to what you have done) so they are perfectly level front to back and side to side - you need them to be secure in this position. From the looks of it, you will now have the biggest gap at the top and you want to cut something, such as a block of wood, that you can use to mark that width of gap all round the fender. Trim to the marked line and the fender will fit the body.

If you go this way, I've got a couple of ideas how to attach the fenders - say if you want them.

Andrew

On edit - dang, George said the same thing better, and with pictures too!

[john]

I had considered removing the "high spots", but doing so would reduce my fenders from 11" to 8.5" wide. I need 11" to keep the outer edge of the fender flush with the out side of the wheel/tire so I am forced to fill in the missing bits.

I appreciate the comments so far (so many so fast). I am lucky in that these fenders don't have a double curve near the trailer body and are curved only along their lengths (from front to back) on the inside edge. There is no curve along the portion of the fender's width that is closest to the body of the tear. This leads me to think that I can make a form out of left over aluminum skin affixed to the inside of the fender. I could then build up the glass on both sides of the aluminum (inside the fender and outside) and leave the aluminum within the fiberglass fender. Is not removeing the mold (I don't care what the inside of the fender looks like) ok? And would there be any problems (expansion and contraction) with useing aluminum as a non removed form?

[SteveH]

John,

Yes, you could do it that way and you could leave the aluminum in there. the only problem I see with doing it that way is the top, or outside of the fender will be rougher and will require more work to make smooth and ready for paint.

[JunkMan]

JohnI don't expect much bondo will be necessary since the flange will form to the top surface of the fender making a nice clean corner, after a little careful cleanup.

Instead of adding a little bondo to clean up the edge, you could use a fender welting like a VW (and several other old cars) uses. It will hide minor imperfections on the edge of the flange.

[Stephen G.]

Glass work is not hard. Go to a auto parts store most sell glass cloth and resin.Put some double side tape on the inside of the fender next to the trailers side. Take some card board that has a straight edge and slide under the inside of the fender and mash it against the double side tape to where it fills in the gap. Once you fill the gap in don't do any resin and glass work while its next to the tear it will make a mess. This will give you a form onto lay your fiberglass cloth. Now mix up some resin per instructions and take a old paint brush and gently brush the resin on the glass cloth taking care not to move it around. Build up layers until it matches the thickness of the fenders glass and add one more layer and over lap on top of the fender and let harden up. Gently remove card board and don't worry if it leaves some paper behind just clean what you can off. Now lay a couple of more layers of cloth and resin on the inside of the fender. This will make it strong. You can at this time make a lip that goes down that you can bolt it to the tears side. Sand the glass and resin smooth and use bondo to finish smoothing it out. Once you get that done you can prime and paint. Sounds harder than it is. I make fiberglass molds using polyester and epoxy resins here at work

[purplepickup]

Instead of adding a little bondo to clean up the edge, you could use a fender welting like a VW (and several other old cars) uses. It will hide minor imperfections on the edge of the flange.

Thanks Jeff. I forgot to mention that, but I do plan to use welting. It looks good and saves a lot of detail work

Plan B, ..... Trim to the marked line and the fender will fit the body.

If you go this way, I've got a couple of ideas how to attach the fenders - say if you want them.

Andrew

I'd be interested to hear your ideas Andrew

[angib]

I'd be interested to hear your ideas Andrew

The obvious one is to remove the fender once it's got a straight edge. Now set it on its side on a flat surface covered with a sheet of plastic (best of all is some cheap counter-top laminate) - the edge up against the trailer wall should now be horizontal and it's reasonably practical to lay up a flange, using the flat surface to make the flange surface.

Although it's not too hard to do the ususal 'paint resin, add glass, stipple glass to wet out', it's also just as good to wet out short lengths of glass cloth or tape on a separate board and then place the wet glass where it's needed - this won't work with glass mat as it will fall to pieces when wet.

The other plan is not quite as good quality, but saves a step. Screw two 1x boards together at right angles (or find something else with an internal corner) to make an angle mould. Two layers of brown plastic parcel tape (I'm guessing you have the same stuff in Merka) makes a good, quick release agent. Lay up a long length of lightweight angle, trim it to 1-2" wide on each leg and cut it into short lengths. Rough up the surfaces and fix the pieces of angle to the underside of the fender with Bondo, making reasonably good joints between lengths - the smooth curve now becomes some sort of polygon on the inside. Remove the fender and laminate over the angles and onto the original fender.

Them's me ideas.

Andrew

[RKH]

Just my $.02 here: For release, I have used kitchen grade wax paper as well.