Home » Public Forums » GMCnet » Crack in the front cap
|
|
| Re: Crack in the front cap [message #219804 is a reply to message #219793] |
Sat, 24 August 2013 21:06   |
 |
SeanKidd
Messages: 747
Registered: June 2012
Location: Northern Neck Virginia
Karma: 4
|
Senior Member |
|
|
Yes, stop drilling in metal or composite will distribute the stress over 360 degrees, usually stopping the crack...be sure you drill at the end of the crack, you may want to drill just beyond where it is visible. You will then need to perform the repair, most cases you will grind a vee shape into the crack on both sides, feathering the edges. scuffing the inside will be important because this is what will reinforce the stress area.
using a fine mesh (usally part of a kit, try marine parts place) mix the hardener into the resin, thorougly brush over the inside surface of the crack area at least 6" on either side, apply one layer of mesh noting the orientation of the weave. brush on more resin/hardener mix, thoroughly soaking the mesh, apply second layer of mesh roating the orientation 45 degrees. squeegee both layers to ensure permiation of resin, cover any remaining dry spots and surrounding mesh with top coat of resin.
apply resin only to visible surface of crack, (where you ground aout a vee and feathered the edge, apply resin so tat it is higher than the finished surface.
allow to cure, sand smooth paint. be sure to wear proper PPE...gloves, mask, goggles.
if you can spackle a hole in drywall, you can fix fiberglass...same principal.
Once repaired a P-3 Orion Nose radome after birdstrike during Desert Storm , the eagle we hit was the size of a turkey!
Sean and Stephanie
73 Ex-CanyonLands 26' #317 "Oliver"
Hubler 1-Ton, Quad-Bags, Rear Disc, Reaction Arms, P.Huber TBs, 3.70:1 LSD Honda 6500 inverter gen.
Colonial Travelers
[Updated on: Sat, 24 August 2013 21:13] Report message to a moderator |
|
|
|
| Re: Crack in the front cap [message #219824 is a reply to message #219793] |
Sat, 24 August 2013 23:56 |
GeorgeRud
Messages: 1380
Registered: February 2007
Location: Chicago, IL
Karma: 0
|
Senior Member |
|
|
I believe that the body is made of SMC, not fiberglass. I found a 3M epoxy product that I used when I ripped off a mirror and tore a hole in the body. I don't remember the product number, but it was a two part epoxy that required a special gun to dispense.
If I can get the number, I'll let you know. I did find a tube of the stuff at a local auto parts store, but gave it to my friend that first told me of this epoxy. It's usually used to bond body panels to a substructure.
George Rudawsky
Chicago, IL
75 Palm Beach
|
|
|
|
| Re: [GMCnet] Crack in the front cap [message #219826 is a reply to message #219824] |
Sun, 25 August 2013 00:43 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
|
Senior Member |
|
|
A cross bonding structural adhesive would be the best choice or smc repair resin. Fiberglass mesh or mat ( I prefer the mat as it builds faster) Can be used with either. Supposedly fiberglass resin does not achieve a good chemical bond to smc. Definitely drill the hole before it gets to the edge of the windshield. Bevel back away from the crack on both sides til you are paper thin at the crack and back to original thickness 3" on either side of the crack on one surface ( interior or exterior). Cut your mat so you gradually fill the bevel( marrow to wide with probably 3 layers of mat. Build it up so the repair is slightly higher than the surrounding surface. Once that has set, repeat on the other side if you have access. If you do not have access to grind a bevel and patch on the back you can rough up (36 grit or so) the backside and bond a piece of polycarbonate to the back which will remain. Rough up the poly prior to bonding and clean all surfaces with wax and grease remov
er (ppg dx330)prior to application. Blow the surfaces after cleaning to ensure complete evaporation of the solvent prior to applying patch material. Cover up all exposed skin prior to grinding unless you love to scratch or soak in the tub for a day. Eye and respiratory protection is a must.
Todd Sullivan
Sully
77 royale
Seattle
On Aug 24, 2013, at 9:56 PM, George Rudawsky <GeorgeRud@aol.com> wrote:
>
>
> I believe that the body is made of SMC, not fiberglass. I found a 3M epoxy product that I used when I ripped off a mirror and tore a hole in the body. I don't remember the product number, but it was a two part epoxy that required a special gun to dispense.
>
> If I can get the number, I'll let you know. I did find a tube of the stuff at a local auto parts store, but gave it to my friend that first told me of this epoxy. It's usually used to bond body panels to a substructure.
> --
> George Rudawsky
> Chicago, IL
> 75 Palm Beach
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
|
|
|
|
| Re: [GMCnet] Crack in the front cap [message #219863 is a reply to message #219826] |
Sun, 25 August 2013 09:45 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
|
Senior Member |
|
|
Here is the repair stuff for the SMC body.
<http://www.gmcmhphotos.com/photos/fixing-the-front-end-bulge/p11516.html>
<http://www.gmcmhphotos.com/photos/fixing-the-front-end-bulge/p11517.html>
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
> A cross bonding structural adhesive would be the best choice or smc repair resin. Fiberglass mesh or mat ( I prefer the mat as it builds faster) Can be used with either. Supposedly fiberglass resin does not achieve a good chemical bond to smc. Definitely drill the hole before it gets to the edge of the windshield. Bevel back away from the crack on both sides til you are paper thin at the crack and back to original thickness 3" on either side of the crack on one surface ( interior or exterior). Cut your mat so you gradually fill the bevel( marrow to wide with probably 3 layers of mat. Build it up so the repair is slightly higher than the surrounding surface. Once that has set, repeat on the other side if you have access. If you do not have access to grind a bevel and patch on the back you can rough up (36 grit or so) the backside and bond a piece of polycarbonate to the back which will remain. Rough up the poly prior to bonding and clean all surfaces with wax and grease remo
v
> er (ppg dx330)prior to application. Blow the surfaces after cleaning to ensure complete evaporation of the solvent prior to applying patch material. Cover up all exposed skin prior to grinding unless you love to scratch or soak in the tub for a day. Eye and respiratory protection is a must.
>
> Todd Sullivan
>
> Sully
> 77 royale
> Seattle
>
>
>
>>
>>
>> I believe that the body is made of SMC, not fiberglass. I found a 3M epoxy product that I used when I ripped off a mirror and tore a hole in the body. I don't remember the product number, but it was a two part epoxy that required a special gun to dispense.
>>
>> If I can get the number, I'll let you know. I did find a tube of the stuff at a local auto parts store, but gave it to my friend that first told me of this epoxy. It's usually used to bond body panels to a substructure.
>> --
>> George Rudawsky
>> Chicago, IL
>> 75 Palm Beach
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
|
|
|
|
| Re: Crack in the front cap [message #219867 is a reply to message #219793] |
Sun, 25 August 2013 11:02 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Bryan,
A crack like this was caused by something being wrong, like the windshield installation. You will probably never find out where it is, but be sure it is through moving before you repair it. Like, drive the coach and see if the spread changes.
The First question I would ask is, "How much patching does your GMC need?"
If this is it, then go to the local West Marine (there is one) and get the West System Repair Kit #105K. It contains some epoxy and things for just this sort of repair. You will also need a small can of acetone. Read the instructions with the kit. They may vary from mine by a little, but it should not be very much.
This next is all based on experience doing repairs on fiberglass and SMC mostly for other people and getting paid for the work.
Take the door off first.
Hand sand the under side as far as can reach.
If you can see the end of the crack (it may be under the windshield), drill a hole that is a diameter close the material thickness.
Wash the underside with acetone to clean it.
Cut a piece of the glass cloth and stick it to the underside. This piece in this place should be less than one inch - maybe only an half - and can be longer than the crack. You will just let the end hang out, it will be of use to in the later steps.
Mix one of the epoxy packages, use the mix and a brush to wet the cleaned underside, then use the rest to wet the cut piece of glass. This is best done on a piece of disposable plastic like the cover of a margarine container.
Stick the wetted fabric under the working area.
Wait until it has cured....
Now, use some little tool to sand the top surface on a long slope toward the piece of glass you put inside. This should be much less than 45° - 10° is more like it. It will end up something like 3/4 wide. you should be down to - BUT NOT through the fabric you put underneath.
Clean this new surface with acetone.
Cut fabric to fill the groove. This may be three or four pieces and the first should only be 1/4 wide.
Remember the wet the surface, wet the fabric and place bit?
Same - same, but now it is easier as you are working on the top surface. Keep adding the strips of glass until you are real close to the surface or even above it. If it over hangs the opening, cut that off when it has cured and you are done.
Once that has cured. Sand down any parts that are above the local surface.
If there are places that still need to be filled, then clean the surface again. Look at the two fillers included and chose one.
Again, mix epoxy, wet the surface and then mix filler with the remaining epoxy and use that to level the surface.
Sand and paint.....
You will find it very beneficial to have an assistant that stays clean and dry. It is also good to have a pair of sacrificial shears (I call them my "wet shears") to clip pieces of glass fiber that stick out or pull off the fabric. If you are mindful, the assistant can clean these shear with either the acetone or white vinegar before the epoxy has cured.
When my shop was working, I bought West Epoxy in 5gal buckets and brushes and gloves in bins. I am sure that I have forgotten or missed something, so just be sure of what you are going to do when you start the next mix.
If you need more help, I am here a lot.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| Re: [GMCnet] Crack in the front cap [message #219870 is a reply to message #219867] |
Sun, 25 August 2013 11:29 |
Mike Teets
Messages: 299
Registered: January 2004
Location: Dublin, OH
Karma: 0
|
Senior Member |
|
|
Matt's instructions are good... the only thing I would add is to mix your
resin and wet out the fiberglass cloth on a sheet of wax paper. Use only
enough resin to wet the fabric and not run. Squeegee excess resin off
while on the wax paper. Doing it this way, you can stay very clean while
installing. More resin makes the repair weaker, not stronger. The wax
paper makes it really easy to smooth out the repair especially on the back
side where you are working blind. Leave the wax paper in place while the
epoxy cures. The wax paper also allows the epoxy to cure without the
sticky blush that forms from air contact. When it is cured, remove the
wax paper and follow Matt's finishing directions.
On Sun, Aug 25, 2013 at 12:02 PM, Matt Colie <matt7323tze@gmail.com> wrote:
>
>
> bhayes wrote on Sat, 24 August 2013 19:58
> > Hello, everyone. Seems I have a crack in the front cap. Here's a photo:
> >
> >
> http://www.gmcmhphotos.com/photos/member-galleries/p50577-crack-in-the-front-cap.html
> >
> > I've heard that drilling a small hole at the end of a crack will stop
> it, but how would I go about repairing the crack? It does go all the way
> through.
>
> Bryan,
>
> A crack like this was caused by something being wrong, like the windshield
> installation. You will probably never find out where it is, but be sure it
> is through moving before you repair it. Like, drive the coach and see if
> the spread changes.
>
> The First question I would ask is, "How much patching does your GMC need?"
>
> If this is it, then go to the local West Marine (there is one) and get the
> West System Repair Kit #105K. It contains some epoxy and things for just
> this sort of repair. You will also need a small can of acetone. Read the
> instructions with the kit. They may vary from mine by a little, but it
> should not be very much.
>
> This next is all based on experience doing repairs on fiberglass and SMC
> mostly for other people and getting paid for the work.
>
> Take the door off first.
> Hand sand the under side as far as can reach.
> If you can see the end of the crack (it may be under the windshield),
> drill a hole that is a diameter close the material thickness.
> Wash the underside with acetone to clean it.
> Cut a piece of the glass cloth and stick it to the underside. This piece
> in this place should be less than one inch - maybe only an half - and can
> be longer than the crack. You will just let the end hang out, it will be
> of use to in the later steps.
> Mix one of the epoxy packages, use the mix and a brush to wet the cleaned
> underside, then use the rest to wet the cut piece of glass. This is best
> done on a piece of disposable plastic like the cover of a margarine
> container.
> Stick the wetted fabric under the working area.
> Wait until it has cured....
> Now, use some little tool to sand the top surface on a long slope toward
> the piece of glass you put inside. This should be much less than 45° - 10°
> is more like it. It will end up something like 3/4 wide. you should be
> down to - BUT NOT through the fabric you put underneath.
> Clean this new surface with acetone.
> Cut fabric to fill the groove. This may be three or four pieces and the
> first should only be 1/4 wide.
> Remember the wet the surface, wet the fabric and place bit?
> Same - same, but now it is easier as you are working on the top surface.
> Keep adding the strips of glass until you are real close to the surface or
> even above it. If it over hangs the opening, cut that off when it has
> cured and you are done.
> Once that has cured. Sand down any parts that are above the local surface.
> If there are places that still need to be filled, then clean the surface
> again. Look at the two fillers included and chose one.
> Again, mix epoxy, wet the surface and then mix filler with the remaining
> epoxy and use that to level the surface.
> Sand and paint.....
>
> You will find it very beneficial to have an assistant that stays clean and
> dry. It is also good to have a pair of sacrificial shears (I call them my
> "wet shears") to clip pieces of glass fiber that stick out or pull off the
> fabric. If you are mindful, the assistant can clean these shear with
> either the acetone or white vinegar before the epoxy has cured.
>
> When my shop was working, I bought West Epoxy in 5gal buckets and brushes
> and gloves in bins. I am sure that I have forgotten or missed something,
> so just be sure of what you are going to do when you start the next mix.
>
> If you need more help, I am here a lot.
>
> Matt
> --
> Matt & Mary Colie
> '73 Glacier 23 Chaumière (say show-me-air)
> Now with 4 working Rear Brakes
> SE Michigan - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Mike, GMCing since 2002
77 Palm Beach, 260, 403
Dublin, OH
http://teamteets.com/gmc/
|
|
|
|
|
|
Goto Forum:
Current Time: Tue Sep 24 02:27:12 CDT 2024
Total time taken to generate the page: 0.02173 seconds
|
GMCforum
Search
Help
Register
Login
Home
