Each of you have asked what materials were used in my recent fiberglass repair project so the following is a recap of the products finally selected. These selections, particularly the Evercoat products, were triggered by a remark I found on Jim Bounds' daily blog in which he reacted to a debate on GMCnet regarding SMC repairs in which he wrote something like this:
"This time, the "old guys" don't have it right--what you should do is follow the advice found on Corvette discussion boards related to later model body repairs."
Jim's advice eventually led me to the Everlast products identified below. Prior repairs in the same area of our coach involved epoxy resins and lots of Bondo, all of which failed when I tried to move a large tree with the left rear corner of the coach and opened up old repairs in the same area. TAP Plastics proved to be a good source of fiberglass fabrics and advice (except for their unfamiliarity with the idiosyncrasies of SMC).
This project was my first venture into fiberglass repair and with these products made it pretty easy to achieve decent appearing results for even a novice. Will the new materials perform well in the long run? Time will tell.
Tape 4" (heavy woven mat for backside use)
Glass mat (3/4 oz -random) for frontside filling
Woven Roving fabric for front side lower layer use
SMC Resin: Evercoat SMC-Compatible Polyester Fiberglass Resin
Filler: Evercoat "Quantum 1"
Quantum 1: http://www.evercoat.com/
Low temp catalyst:
High temp catalyst:
Clearcoat finish: KBS Coatings "Diamond Finish"
(Purchased but yet to be applied, can be applied by roller)
Painting was done using the "$50 Rustoleum paint job" roller methods found on many hot-rod bulletin boards and YouTube videos with the exception of use of "Rust Stop", a private-label version of Rustoleum carried only by Ace Hardware---with the big advantage that Ace Hardware can color-tint the paint to match. Johnb
For those of you that are using Kroil which
is good, there is a better solution.
Machinist's Workshop (2007/04) magazine tested penetrants for break out torque on rusted nuts. Significant results! They are below, as forwarded by an ex-student and professional machinist, Bud Baker. The magazine arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a” scientifically rusted" environment.
Penetrating oil Average load
None 516 pounds
WD-40 238 pounds
PB Blaster 214 pounds
Liquid Wrench 127 pounds
Kano Kroil 106 pounds
ATF-Acetone mix 53 pounds
N.B. The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch and we all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.
Here are the results of the test of the ATF/Acetone verses PS/Acetone.
Although neither material mixes into a homogeneous solution the ATF/ Acetone combination does not separate very rapidly as compared with
the PS/Acetone combination that separates almost immediately after shaking.
I have not yet tried the AFT/Acetone mixture, but I have several friends that use it and swear by it.
The pressurized sprayers are the best solution when using this mix as
Bob & Terry have suggested.
Harbor Freight also sells cans like that:
*ITEM 1102-DAA **http://tinyurl.com/yg5587q*
*ITEM 65297-DAA **http://tinyurl.com/ygb46m8
Seem to be only available in the stores (harborfreightusa.com) and not
You can draw your own conclusions!
Several of our members have tried it and swear by it. J.R. Wright
If you really, really, really, want to make it all disappear then make a single hole and cut an aluminum patch that fits as exactly as possible into the hole. Make a second patch about an inch larger overall. Flush rivet the larger to the inside of the roof with suitable sealant between, then fit the smaller into the hole and flush rivet it to the first.
Plan 2, flush rivet a single patch to the inside of the roof covering all holes and fill the holes with bondo.
Plan 3, put rubber washers over suitable sized screws, coat with sealant and use them to fill the small holes, make an aluminum patch to cover the large hole(s), coat with sealant and screw in place with sheet metal screws or pop rivet.Glenn Giere
This is how I patched my Roof Vents. It is a lot bigger
than what you need but the same principle.
Do you know if anyone has ever attempted to Aluminum TIG weld a to repair a roof hole?
Don't forget that the ceiling, like the walls, has been sprayed with
VERY flammable urethane foam. Welding it without totally
protecting that foam is an almost sure way to destroy the coach.
Elem Fayard (a deceased Dixielander famous for Bob Drewes' and Tom Whitton's amazing coaches, as well as many of the fiberglass accessories' designs) burned his 23' to the ground in just a few minutes when attempting that.Ken H.
If you are talking about the outside body belt molding that goes from side marker light front to back, I know Cinnabar has it as do I believe the Jims and Gateway lists it and probably Grandview as well.
It all depends. You don't say what motorhome model you have but I looked you up and find that you have a 1977 Royale.
The GMC finished motorhomes at that time used SCM (Sheet Molded Compound) the same as used on the main bodies of the GMC.
Since you have a Royale really all depends on what Coachmen Industries decided to use at the time or perhaps what a prior owner put on.
There have been people that have produced a laid up fiberglass T skirt.
If you look inside the T skirt you can usually tell. If it is smooth and has mold marks with smooth ribs it is probably SCM. If it is rough fiberglas then it is laid up work. Emory S
Our water tanks are polyethylene;
here's a video I ran across on
> how to repair polyethylene. It mentions that the material has to be
> "flamed" before repair. <http://www.tripphop.com/
. The fresh water tank is polyethylene.
If you have the Maintenance Manual X7525 check out page 24L-3.
Better use a piece of polyethylene instead.
You can get pieces of it by just cutting strips from a plastic milk bottle.
Your idea of using a solder gun is good. Weller has a large flat tip available that let's one "paddle" the melted surface.
Sometimes, though, the plastic gets so old and brittle and the plastisizer dries out so it won't hold together even when welded.emery
for 73/74 coaches
I used "CRL Black 5/64" Sealstrip Glass Tape" for the fixed windows. One roll was about twice as much as I needed for our 1973 23' coach. Soapy water helped with getting this back into the channels once the tape is wrapped over the glass edges. (it's not really "tape" since it's not sticky). Trim the rubber tape back after the window is in place.
I also used the usual fuzzy channel stuff others have mentioned for the sliding windows. At the time JimK was out of fuzzy channel, so I got it from vintage trailer supply. Others have mentioned other sources/versions which may fit more tightly, but the stuff I got is holding up OK after 4 years.
When you've got your 73/74 windows apart, make sure you apply RTV or other sealant to the splines that hold them together or it'll still leak. See:
The above is only for 73/74 coaches. The window construction changed completely in 75 - KB
They have 200' minimums but it is not
expensive at all. Jeff
They had to make it? More like order it from overseas...
Good stuff anyway. Chris
At the GMCWS rally I saw a few coaches
with the white rubber trim, it looked good, of those that I asked they
didn't know of a source for it. The trim was in when the coach was
Any problems with the white rubber trim?
the problem is that your windows were not designed to use it. There is a groove in the aluminum extrusion of the window frame that the white rubber trim goes into.
You don't have this on the earlier windows. emery
a source for window channel material.
I got mine from Danno
in Port St. John FL. www.dannoenterprises.com, 321 452-8101. Their part
number is AS1268, (They reference number 75-0639 which is the manufacturers
Mine is 8 foot but perhaps they have longer available. It was $8.00 per 8'
Cockpit Bulging "Chipmunk Cheeks"
Here is one photo album by Richard Sowers...
The bulging fiberglass on each side of the
cockpit is sometimes called "Chipmunk Cheeks"
and is present to some extent on most GMC's.
I suspect most of us have just filled the gap with spray foam or caulk and avoid looking down the side of the coach.
A more complete fix is to remove the rubber rub strip on the beltline and install flat head screws from the outside into the inner wall before the
sealing. Replacing the rub strip covers the screw heads.
The most complete fix I've seen was by a Corvette specialist who gave a presentation at a GMCES rally several years ago: He used some sort of two part adhesive, the specifics of which I don't recall, to adhere a fiberglass angle to the inside of the fiberglass after pushing it into place from the outside. Both the adhesive and screws held it the floor.
You might pioneer the use of the aluminum angle adhered with 3M 5200. I'd back it up with the screws through the beltline though. KenH
The plastic is ABS. I repaired some cracks
and holes in mine using West System epoxy.
For cracks and small hole I used aluminum duct tape as backer for the epoxy.
For the larger holes I also used fiberglass mat as reinforcement.
To simulate the pebble finish I used A SEM product for that purpose and after painted the panels with SEM. Tony
PHOTOS BY ARCH
BODY REPAIR (SMC)
a few years ago we had a Toyo tire co. representative speak at an SOB rally.
His position was that they do no
good; he maintained that the vast majority of the surface deterioration
of tires is due to ozone, not sunlight. Covers don't slow down
The same tire rep, during the same
presentation, was adamant that NO tire "protectant" should be used.
He would not, for obvious reasons, name the product, but said
that one of the most popular would definitely harm their (Toyo) tires
-- and probably others. KenH
FRONT WHEEL LINERS
I've some cracks in my fender liners and have tried fiberglass as a fix but it
doesn't stick. What is the best way to patch these things? What is the
best way to prep for painting? Glen,
The only satisfactory repair on the front wheel liners I know of is plastic welding. JohnS
successfully welded cracks in the wheel wells
by using a plastic welding gun and a strip of plastic cut from the
bottom edge of the wheel well. The plastic
welding guns are available from Harbor freight for a one time repair or
a quality gun can be had from any autobody supply house. HTH.....Terry
REAR WHEEL LINERS
EARLY COACH (73 - MATERIALS PROBLEMS)
Being # 295 off the line from the
beginning of production, there are several things you may want to look
at. I like early model coaches, have 2 of them. I look at
them as a "box of chocolates", you never know what you have to you bite
o The floor is a single layer plywood construction, later models had a composite wood, foam, aluminum floor construction, The mufflers had a nasty habit of burning and charring the bottomside of the floor. 74 models started in with heat shields between the floor and mufflers.
o Steve Ferguson found that the early coaches "A" arms needed more reinforcement, you want to be sure there are no crackes around the lower ball joints and that the shock mounts are not loose.
o Locating the air suspension tank under the battery was a brain fart, also the regulator for the system was reading line not tank pressure. A replumbing and relocating of the system would really help it work better. Get one of JR Slaten's "Power Level II" dash valve kits-- solds 50% of your air ride troubles.
o Make sure the screws that hold the window latches are in good shape, if you loose a latch---- well, lets say they are made of "unobtanium"!
o The dash AC systen stinks, collect enough $ to add an under dash AC eveap/blower if you want ant dash AC cold air.
o The "A" frame windows (the window frame holding 3 pieces of glass at the driver and pass. seats) were put in with screws on the early coaches. They figured out how to install them better later. These windows are "leakers". We seal completely around the frame to body ---- of course you could drill holes in the floor to let the water out!
o The rest of the side windows on the early coaches were also "leakers". The frame is a 4 piece "brake apart" design with no sealant at the joints.
o The rear panel screws on a 73 were threaded into brass "inserts" in the SMC body. I would not suggest you try and take them out. They are usually rusted in place. On 73 models we usually sand blast the screws, hit them with Ospho (a rust killer) then prime/seal and paint them the body color and leave them alone. Removing them all could end up being a big job.
o The generator compartment covers sometimes leak fumes into the interior, I would remove the generator, clean it up and totally seal and insulate the generator compartment. There was a story I heard from on of the interior design engineers at a GMCMI convention who told about the early coaches and the less than wonderful detail of the sealing of the generator. Since, I have seen what she was talking about.
o If the motor still uses a point dist, loose it for an HEI set up. Gives a much better spark and easier to maintain.
o Don't lock the entry door without using a key, I have seen early coach latch mechanisms bind up. I would just use the key on any model, not push the stem down on the inside and hold the handle---- you just never know!
o Keep the rear suspension pins lubed, the early coach used smaller diameter pins-- no problem if you keep the greased up.
o Do not blow the air bags completely and drop the back to the ground, the wheels hit the liners and crack them. Later models had cut outs to provent this.
o Your coach was originally plumbed with copper pipes on the fresh water system. 1973 only, later models used plastic piping. Sweated copper fittings do not like to bump and twist going down the road, watch for leaks!
So now that I've scared you to death, the 73 models are no bigger trouble than any of the other ones, like I said I like them, I have 2 --- actually 3 of them. Just know you have the first year, prototype model and watch for this special stuff. There are other things about the 73 modles, didn't want to make this post too long.
Let me know if you have any other questions, Jim Bounds
JB Weld worked for my grill. That was recommended by Max Pardy at Buskirk-Rush. That's how they did it. ErvT
I have made some repairs to my grill. I had several cracks, all the nubs that
go through the smc body were drilled out and some pieces were missing.
The grill is made of the same material your black pipings is, ABS.
for cracks, try to feed some of the solvent for gluing ABS into the crack and let set. It should be a strong hold.
For areas missing material, you can take a piece of the ABS pip and shred it to small bits, a little larger than sand, I just cut it with a hack saw blade and used the chips that were made from cutting.
form the piece you are replacing on the VISIBLE side with masking tape, if it needs to be shiny, use a clear plastic bag where it will touch the material, keep as smooth as possible, no wrinkles.
make a mush of the ABS chips and solvent until it is pastey and thick, then on the back side, smear the paste into the space to be occupied with new material. Give a few extral pushes by the sides where it touches the old material. It is ok to put a bit more on than needed, it will shrink over a week to two week period as it cures.
Any space between the old and new material can be filled in again and any rough surface can be bondo-ed. Sand smooth and paint.
Where I tried to replace my nubs I found I had too little area to glue to so am trying a slot design now. Too new to report on now.
I had good luck with this and it keeps the material more or less virgin, incase there are future repairs.
And if you are careful, it isn't all that messy either. I mixed and applied the material with a popcycle stick.
If you are filling a void, be aware that
the material will shrink a bit as it cures so dont paint for a couple
weeks. I had waited a few days, being my first attempt at repair and then painted. A week or so later I
could see where the material pulled in slightly, not unattractively,
but I know its there.
This will get you fixed. LarC
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