Armstrong A/C Shroud Refurb Ideas

[roadeo]

Shroud Refurb
There were/are a small number of members who have attempted/succeeded in refurbing their shrouds. Probably using fiberglass in most or all examples.

I am in process of trying to round up all the scattered posts and threads. I am wondering how the fiberglass has held up.(I am assuming most have just layered one side of the original shroud, probably the inside. I plan to attach my old shroud upside down to a plywood work bench and rig up some cross bracing (prob dowels) to stabilize it as "plumb" as possible before attempting to embed fiber cloth inside in many places. If I apply a thick coat of resin with brush and then lay the DRY cloth into it, then apply more resin over the cloth, working into the cloth with a putty knife, what do you guys think I will have? a mess??

I am hoping that at the top (actually the bottom) of shroud where it mates to roof of trailer, I can leave a margin of say 1.5 inches of the cloth not resined.
Then after all has dried, I foresee somehow folding this selvedge inward, clipping it with alligator clips and twine to opposite side and resining those selvedge edges. Giving myself a lip at the bottom (I hope).

I have not used fiberglass in many a moon and then it was with poor results. Am I peeing in the wind here??

Any reason the resin would not bond to the ABS satisfactorily?
If all works then I will figure out how to re-surface (paint) the outside.

[roadeo]

I just found another thread on the subject of shroud refurb;

http://www.airforums.com/forum...ead.php?t=8854

Originally Posted by TC Williams

tcwilliams
4 Rivet Member
Huntsville, Alabama
1967 26' Overlander
Subject: Possible repair technique
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I'm lining up possible repair techniques for my A/C cover. Right now, I'm assuming the cover is ABS plastic, which means most glues and/or resins won't stick to it for very long. In the past, I have been able to repair similar things with fiberglass and resin by drilling a bunch of quarter-inch holes in the article, and fiberglassing both sides. The holes allow the resin to 'lock' both sides together. The A/C cover, however, may be a bit thin for this technique.
I'm getting ready to experiment with, in effect, "making" new plastic: Cut/Grind/whatever some ABS plastic into shavings. Put the shavings in small glass jar, and pour a small amount of methly ethyl ketone (MEK) in with the shavings. Cover tightly. Let set a while for the MEK to dissolve the shavings. Too thin - add more shavings; Too thick - add MEK. The right consistency should work well for cracks. Thin it a bit, and it will make excellent solvent weld to affix new pieces of plastic.
Keep in mind that, although you want it to look as good as possible, the height it's mounted will make it difficult to spot flaws.
Just some thoughts,
Tom

Are you sure that fiberglass resin will not stick to one side only of the Armstrong shrouds? I am assuming that they are ABS plastic, but as you know there are many different ABS plastics.

Did you actually try it on your shroud and have it fail to stick?

Are there different formulas of fiberglass resin for different overlay bases?

[malconium]

I just recently worked over my shroud to repair some cracks in the corners near where the mounting screws go through the shroud. I bought a fiberglass repair kit from GI joes and packaged under the Bondo name. I put the patching all on the inside. I used a cheap foam brush to both mix and install the resin which seemed to work just fine. While it is too early to tell the long term effect of my repairs it did seem to stick pretty well. I bought a can of the Krylon paint that is supposedly especially suitable for plastics. The store where I bought it did not have an alumuminum color but they did have a flat pewter color which worked just fine for my tastes. It is a nice soft dove grey.

I don't see any reason why your flange idea won't work but suggest that you may have to add 1 or 2 more layers there to get enough thickness. Maybe you could lay up some strips of fiberglass on a flat surface (covered with something the fiberglass won't stick to - will wax paper work?). You would then have some nice flat strips you can laminate the loose flaps too. They might also help support the flaps.

Malcolm

[roadeo]

from; http://www.airforums.com/forum...ad.php?t=12879

Originally Posted by thenewkid64

thenewkid64
Moderator
Posts: 3,672
Tampa Bay, Florida


I have done some reinforcing as you described, it works well.

You need to lightly sand the surface before applying the resin. The cloth should be in the smallest pieces you can handle since the spots that normally need work are compound curves and corners. You want the cloth to stay flat, not bridge, big pieces will tend to bridge in corners. Over curves the big sections are fine.

If you have holes I recommend using some blue masking tape on the outside. This will allow the resin to fill the void, and with a bit of sanding afterword offer a nice surface to repaint. Be sure to remove the tape in the first hour or so after layup.
__________________
Brett G
WBCCI #5501

newkid64 did you have chance to see the work after any length of time?
i.e. did the stuff stick?

Mr.Williams' post above gives me pause to make sure before I go to alot of trouble. I can of course do a small sample, but don't want to purchase the stuff if it might not hold?
Any advice on fiberglassing would also be appreciated.
Somewhere I have seen a fiberglass thread but am having trouble finding it. I'll keep searching.
Thanks

Malconium, thanks for the input, I am definately gonna try it if the stuff will just stick. I saw a thread you contribed to but cannot now find it, I would like to add it to my list, do you know where it is?

[malconium]

Hmm... I just read the post about maybe not sticking to ABS for very long that was added while I was writing up my repair experience. I guess time will tell if the repair works. It did seem to stick OK to mine though. Also the material did look to me to be more like figerglass than ABS. I sanded the surface a bit to get the patch to stick better and it did scratch like I would have expected fiberglass to. Isn't ABS a bit harder to scratch?

Also take a look at the recent thread titled "New a/c shroud!!" where Andy says that they were made of fiberglass.

Malcolm

[malconium]

Roadeo,

Which thread topic are you looking for? One thing you can do to help find threads where a given user has contributed is to click on the user name next to a given posting. You will get a pull-down menu where one of the choices is "Find More Posts by...". Give that a try or let me know the topic and I will see if I can help you find it.

Malcolm

[roadeo]

Malcolm I went thru your posts and apparently I was thinking of someone else's posts. Thanks though.

[roadeo]

Have just viewed TC Williams of Alabama excellent web page on his shroud repair. The repair is outstanding from an appearance standpoint for sure and having read of other of TC's repairs I suspect from a durability standpoint also. Thanks for the excellent pictures and report TC. I plan to burn a copy of the whole subject to CD but first a few more questions please.

This web page is a must read if you are overhauling a shroud.
http://www.knology.net/~tcwilliams/ShroudRepair.htm
referenced from ASForum thread;
http://www.airforums.com/forum...ad.php?t=15787

Do not know the exact age of his repair,nor how long it has sustained sun and weather and road rattle (vibration etc) but would appreciate a report on that from TC if possible.

TC what is the brand name and ID info of the ABS Cement you used?
How much would you estimate is needed per square foot of cloth?
Approx cost of can?
Is the cement black in color when in can? or does it turn black only after it is applied to the cloth and existing ABS?

When you made your patch cloths did you apply the Cement to both sides of the raw cloth or just one? How flexible was the patch cloth after cure?

Could you be more specific as to the process of applying the raw cloth and embedding it onto the existing ABS please.(as you did in some of the interior reinforcement)
i.e. Did you first coat the old ABS then lay in the cloth dry and then another coat of Cement? or did you saturate the cloth first?

How much time do you have to work with it before it sets too much for adjustment?
If you get the stuff on your hands will it come off? (Within a decade)
Is there a cleaner for hands and tools?
What is approx time of cure to touch? Final cure?

Does the masking tape (it appears you used) work satisfatorily as a dam to hold the patch embed? or does the ABS Cement "burn" thru the tape?
Can the tape be easily removed from the patch after cure? If not, then all "dams" would need to be on the interior of shroud...right?

TC can you opine on a comparison of the relative strength and permanacy of the ABS Cement saturated patches vs resin saturated cloth.

Finally did your paint stick to the black patch cloth alright or did you have to prep it in some way? Did you paint the inside?

Thanks
roadeo

[summerkid]

Originally Posted by roadeo

Is the cement black in color when in can? or does it turn black only after it is applied to the cloth and existing ABS?

No, I can vouch for the fact that the cement in the can is actually a pale, pale aqua color that goes through many transmutations on its way to becoming black outside the can. In fact, at points it is a peach/linen look.

[Hit'nMiss]

I broke one of my large Pet Porter dog crates unloading it from the truck a few weeks back, and just happened onto this thread . I am going to try the Williams Method on the crate. I think it is ABS. I went to Lowes and got some of the ABS cement but was confused which one to get. They had a milky colored one that was an allpurpose for ABS and PVC and other plastics. And the black stuff for ABS only which I bought. Must go to a auto supply store and get some fiberglass cloth although my friend says why not try the blue fiber mat that is in an AirConditioner filter. I've got some of that here somewhere.I wish I knew about cleaning up after this project. There is no way no time that I don't get something messy on my hands and elsewhere.
There are no clean up instructons on the can.
I am hoping the stuff doesn't melt the existing ABS and make matters worse, since all I have now is cracks and the fracture is not in pieces.

Oh Rodeo the cement was about $5.25 for the larger sized can the small was $2.22. It was Oakley brand. Thanks for the link. That is a very helpful website if this works on my dog box, I wonder if it will work on the Airstream bath fixtures and the End Dome?
If you got a Private Message from Mr. Williams in answer to your questions it would be helpful if you would post them here IYDM. It will be a few days before I give this a try.

Wish Me Luck,

Flicka

[roadeo]

Originally Posted by summerkid

No, I can vouch for the fact that the cement in the can is actually a pale, pale aqua color that goes through many transmutations on its way to becoming black outside the can. In fact, at points it is a peach/linen look.

Originally Posted by HitnMiss

I broke one of my large Pet Porter dog crates unloading it from the truck a few weeks back, and just happened onto this thread . I am going to try the Williams Method on the crate. I think it is ABS. I went to Lowes and got some of the ABS cement but was confused which one to get. They had a milky colored one that was an allpurpose for ABS and PVC and other plastics. And the black stuff for ABS only which I bought. Must go to a auto supply store and get some fiberglass cloth although my friend says why not try the blue fiber mat that is in an AirConditioner filter. I've got some of that here somewhere.I wish I knew about cleaning up after this project. There is no way no time that I don't get something messy on my hands and elsewhere.
There are no clean up instructons on the can.
I am hoping the stuff doesn't melt the existing ABS and make matters worse, since all I have now is cracks and the fracture is not in pieces.

Oh Rodeo the cement was about $5.25 for the larger sized can the small was $2.22. It was Oakley brand. Thanks for the link. That is a very helpful website if this works on my dog box, I wonder if it will work on the Airstream bath fixtures and the End Dome?
If you got a Private Message from Mr. Williams in answer to your questions it would be helpful if you would post them here IYDM. It will be a few days before I give this a try.

Wish Me Luck,

Flicka

Hit&Miss I have not recieved any e-mails from tc williams, Sorry, but maybe he hasn't seen the post? I hope you have good luck and will let this thread know what happens. I think you meant Oatey brand cement.www.oatey.com Besides the All-purpose Cement they also make a Milky color ABS only cement. I have no idea if the All Purpose would work.
(Apparently Summerkid has confused ABS Cement with some PMS product or maybe her wrinkle cream)(Her above post was, as always so prescient, informative and shed much light on a serious subject. Obviously the only dumb questions in her clear little mind are those she didn't ask).
Lowes doesn't carry it but some plumbing supply wholesalers do. All I can find out is that it is colorless only to make it less messy.
All of the various non-VOC* cements are very dangerous to use so you need to be real careful and not inhale any of the vapors if possible. If you have or can borrow a good respirator you'd be better off.

I never thought about using this process on the bath fixtures or the end caps but if so I think I would use the milky color. Assuming that it will set up the same. I am afraid I am just going to have to do some experimenting first. I liked your thought of using the fiberglass that is inside the central a/c filters. That stuff is cheap and might work. Not sure it could be easily "soaked" with the solvent though.
I think you are right that most dog crates are probably some type of ABS plastic. Not sure how you can tell for sure. Maybe call the manufacturer, and you can probably get their number from Pet's Mart or do a Google.

roadeo

*VOC are vapor reduced chemicals and solvents required in California and where specified.

[TomW]

Originally Posted by HitnMiss

I broke one of my large Pet Porter dog crates ...I am going to try the Williams Method on the crate. I think it is ABS...

If that truly phenomenal & inciteful method of repair that Mr. Williams outlined is going to work in your situation, you need need to confirm that your crate is of a material that will work with ABS cement.

Dab some acetone on the crate. If, after a minute or so, the plastic gets tacky, then the Williams method will work. If not, you will need to purchase a new crate as the type of plastic used can only be heat welded.

Best of luck!
Tom

[71excella500]

I used fiberglass to fix my AC shroud. then sanded it to clean is up. Body filler was the last thing I applied to smooth the ruff spots out and make it nice and smooth. Sanded it really nice and smooth then painted it. To two days but in the long run it was worth it. all painted and looks like new.

[Anon]

Originally Posted by malconium

I bought a can of the Krylon paint that is supposedly especially suitable for plastics. The store where I bought it did not have an alumuminum color but they did have a flat pewter color which worked just fine for my tastes. It is a nice soft dove grey.

Malcolm

I used the Krylon Fusion ALL over the Minuet. That stuff is indestructable! I sprayed my shower tub with it two weeks ago. The can says that it is chip resistant after 7 days. I got in the shower tub and walked all over it with shoes on!!! It would not peel, chip or crack! That stuff is AWESOME!!!!