Drilling Fiber Glass Fenders.

[Mightydog]

Sorry if this question is a deuce, but I have a pair of R W Johnson fenders that are beeeeeeautiful. To keep them that way while they are mounted on the trailer, I need to know how to drill them for the bolts to hold them on.

Fast speed or slow?
Titanium bit?
Put a piece of backing wood on it?
Standing or sitting?
Light beer or dark?


I dunno--help!

[mudgepondexpress]

I think the best bit for this work is a Unibit! they leave a smooth hole, don't grab and can actually do a small taper/countersink. Use a soft wood backing and a medium speed (the unibits need a little more speed than the regular bits, but I don't turn them faster than half "throttle" on my Milwaukee 1/2 hole shooter...aprx 400-500 rpms.

Kenny

[mikeschn]

Steve drilled the holes in mine, so I'd have to ask him... However I can tell you that he used threaded inserts in the sidewalls, and panhead type bolts with a bumper washer underneath it to spread out the load...

Mike...

[Mightydog]

Good stuff everyone.

I knew we picked up that package of unibits at Costco for a reason.

Yeah, thanks for the mention, Mike. We were thinking of using fender (!!) washers on the inside and outside to spread the load. Imagine using fender washers on fenders! After all these years of using them for everything else.

[rooster]

You might want to check out "Elevator bolts" at your hardware store. They have a large flat head that will sit flush with the inside of your tear. I used 1/4" or 3/8" and the flat head was about 1-1/4" or 1-1/2" across. Just a 3 cent thought . . . .

Jim,

[SteveH]

The main thing with fiberglass fenders in not the drilling of the holes, but the washers you use bolting them on. Always use the largest fender washer you can get with fiberglass. If you don't they will work under the fastener and the bolt/nut will literally eat all the way thru the fiberglass.

[Steve_Cox]

Looks like many different ways to drill.. I used a brad point bit backed up with soft wood. Also made neoprene washers the size of the fender washers I used. Elevator bolts, didn't use them but that's a good idea if you need a clean flat surface on the bolt head. McMaster.com has them. I used tee-nuts behind the trim on my TD then ran the bolts thru the fender with the neoprene washer, fender washer, nylock nut.

[Steve Frederick]

Steve drilled the holes in mine, so I'd have to ask him... However I can tell you that he used threaded inserts in the sidewalls, and panhead type bolts with a bumper washer underneath it to spread out the load...

Mike...

Yup! Use a sharp bit, I used 1/4". As Mike mentioned, I used threaded inserts, also for 1/4", bolted them on with 1" long S/S bolts with fender washers, (hence the name?), with a bit of silicone sealant in the insert, as a waterproofing, locking measure. I think I used 6, or so bolts/side..Mike could count them, Mine is in a shelter, buried in snow!

[Mitheral]

I really like stainless for stuff like this. Yes it's like 5-10X the cost but you need so few and they won't rust solid after five years of constant sand and water spray. Plus you won't get ugly rust stains on the fiberglass.

One other hint: The holes in your fenders should be a bit larger than the bolt you are using. Allows for some fine adjustment and it lets the fender expand and contract at differnent rates than the wood body.

[asianflava]

Yes a Unibit or Christmas tree bit is probably the best for drilling the fiberglass fenders. It also makes it easier because you don't have to go back and find the next size if you have to.

I'd also suggest wearing some disposable gloves. My hands were itching afterwards. Money never came my way so I assume it was from the fiberglass.

[angib]

I'd also suggest wearing some disposable gloves. My hands were itching afterwards. Money never came my way so I assume it was from the fiberglass.

If you are sensitive to fiberglass dust (most people are who don't use it all the time), it isn't very effective to try to wash it off - the trick is to get a lump of putty or anything sticky like that and roll it around your hands - the stickiness will pull all the fiberglass dust off.

You can use sticky tape, but unless you've shaved your hands first, you're gonna wish you'd decided just to put up with the itching.......

Andrew

[Mightydog]

Again, thanks for all of the help everyone.

[Bandit]

You may also want to use some easy stick masking tape over the area to be drilled. This will help eliminate and splintering and chipping.

[fornesto]

I would second the use of neoprene, or other foam-like washer. This might keep the big washer from cutting through the fiberglass.

[Denny Unfried]

I just used a regular drill bit to drill my R. W. Johnson fenders. Then, I transfered the holes to the side of the trailer and installed threaded inserts without going all the way through. Some short studs with Locktite on them were installed then fender washers and nuts. Kind of a ghost image superimposed below to illustrate. Haven't fallen off yet

Denny