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Sandi & Bob · 03-22-2012, 11:59 AM

We are doing some minor repairs and maintenance. Some of the seam areas appear to need fresh caulk/sealing. Where do I use the Vulkem and where do I use the Acryl-R? I know the Acryl-R is used on the roof seams but what about around the windows and door, where the body meets the trim at the bottom and across the top of the awnings? Just want to do it right, once!!

perryg114 · 03-22-2012, 12:04 PM

I think you done opened up a can of worms. Acryl-R and Parbond are used in areas where there is a thin gap. Tempro-635 (gray) is used for larger seems like at the top of windows and doors. Some folks prefer Acryl-R over Parbond because they say it lasts longer. The Acryl-R is more expensive and you have to buy an oil can like dispencer.

Whatever you use make sure the area you are going to seal is clean and free of all old adhesives. Silicone requires extra cleaning to get it off.

Perry

Gene · 03-22-2012, 12:59 PM

I have used Acryl-R anywhere there are silver colored metal parts because it is the same color and sticks very well.

For the many things on the white roof, a white Sikiflex works well. Go to the Airstream website and check the store tab—then look for exterior stuff and I think it explains which Sikiflex to use for that. It can be used on some windows too, but the color isn't perfect. It comes in tubes and is used in a caulk gun. Once opened, it is difficult to keep the stuff in the applicator from drying and rendering the tube useless. Some say freezing it works. I haven't tried that.

Acryl-R comes in a can and you can buy it and the pump. Last time I looked (quite a while ago) Airstream's price was competitive. The Acryl-R I opened a few weeks ago has not solidified in the pump and I used some more yesterday.

The Acryl-R is expensive, but so are leaks. It can be messy to use (as is any sealant) and you need to have a powerful solvent to remove smears and dripping blobs all the time. Once dried on your hands, it will take a lot of energy to get off. I believe you can buy it in a tube and I don't know whether that is a good choice.

I don't know much about Vulkem, but I think one use is inside window frames—I know the panos have covers inside that can be removed and lots of sealant can go in there to stop leaks. They had to re-do that at the service center when we were still on warranty. Sometimes the term "vulkem" is used for several products that do the same thing.

Gene

Soyboy · 03-22-2012, 02:07 PM

Suggestions (that someone else on here recommended) store Acryl-r in a freezer bag and put a pin or piece of wire in the end of the dispenser. I do this and it has remained useable over the course of a year in storage. Just remember to let it warm up before using, I put it out in the sun when I know I am going to be checking seams. Some folks suggests putting the can in a pan of "hot" water to help it get ready to dispense. I think it is pretty good stuff. It is sticky, but once you get the hang of it you shouldn't be making much of a mess, the dispenser works well. I keep mineral spirits on a rag ready for any cleanups. I havent' tried Vulkem yet. I have used ProFlex RV Sealent by Geocel on my previous SOB and on the Airstream roof with good results.

Flame away...... ;-)

Sandi & Bob · 03-22-2012, 02:11 PM

what about the awning? settle a bet for me. I say use the Vulken caulk for where the awning meets the camper roof and my husband says Acryl-R. Who's correct????

Gene · 03-22-2012, 04:04 PM

A pin with a "handle" to insert in the Acryl-R dispenser works so far—it came with the pump. You have to press pretty hard on the pump handle to get the stuff out, and heating it would probably make it easier, maybe too easy if you are trying to run a thin bead.

Gene

Frank's Trailer Works · 03-22-2012, 04:26 PM

I really do not know why it bothers me so much, but it does. Vulkem was bought by Trempro. What used to be Vulkem is now Trempro 626. It is a texturized polyurethane sealant. Sikaflex does NOT make Vulkem and Trempro 635 is NOT Vulkem.

VULKEM is TREMPRO 626

Done with my rant and yes, it really does bother me.

Sandi & Bob · 03-22-2012, 04:32 PM

I really don't care so much about storing the stuff as long as I get the right product on the right seam, but thanks for all the input...

wahoonc · 03-22-2012, 05:19 PM

If the gap is more than about 1/8" of an inch go with the Vulkem/Trempro less go with the Acryl R. I quite often use NP-1

which is similar to Vulkem but made by BASF (Sonneborn)

Aaron

Soyboy · 03-22-2012, 08:49 PM

Gene, I had that pin and I lost it, so I had to use a piece of wire that I had. Let it warm up and it won't be so hard to pump.

perryg114 · 03-23-2012, 11:54 AM

Ok so what is the difference between 626 and 635? It looks like both are good sealants. I would take the 635 over the 626.

The 635 has better elongation and tensile strength and it cures faster. The 626 appears to be a harder material but it is not going to take as much flexing before it breaks or comes loose. So I don't think that telling folks to use Trempro 635 is leading them down the path of darkness, let the facts speak for themselves.

Trempro 626
Cure Rate 48 - 72 hours
Sag Resistance Non-Sag in 1/2” Joint
Shore A Hardness 35 - 45
Tensile Strength 150 - 200 psi
Elongation 210 - 230 %
Stain and Color Change None
Weight Loss, 24 Hours (Uncured) Max. 10 % at 100oC
Peel Strength on Aluminum 15 - 20 pli

Trempro 635
Extrusion Rate 20-30 seconds
Skin Formation 40-60 minutes (typical)
Shore A Hardness 22-32
Tensile Strength 250-350 psi
Percent Elongation 400-600%

Perry

Quote:

Originally Posted by 62overlander

I really do not know why it bothers me so much, but it does. Vulkem was bought by Trempro. What used to be Vulkem is now Trempro 626. It is a texturized polyurethane sealant. Sikaflex does NOT make Vulkem and Trempro 635 is NOT Vulkem.

VULKEM is TREMPRO 626

Done with my rant and yes, it really does bother me.

Frank's Trailer Works · 03-23-2012, 01:17 PM

Perry, Your really good at looking up technical info, but not so good at reading what I said.
Maybe I can send you a Xerox. You can read it with a Coke wrapped in a Kleenex.

There are many differences between the two products Trempro 635 and Trempro 626. One formula used to be called Vulkem, one did not. The texture is the main thing. The cure rate, however, is why I use one over the other. When replacing large panels(sometimes 16 foot in length), we prefer to not have the material curing before all the rivets have been set. Half cured sealant causes gaps where real VULKEM does not. Even after many hours of being held by just cleco, we can buck the seam and get excellent squeeze out. Try that with Trempro 635. Instead of a smooth creamy ooze, you will get semi gelatinous globs. It is also much easier to clean wet VULKEM or wet polyurethane sealant than cured or even semi cured. A free tip... WD40 cleans it off very easy as long as the rag surface is clean. One two strokes and you need to fold it to a new face.
All that technical info is great, however in the applications we use it, it is NEVER put remotely close to the levels it is designed for. Use whatever product you want, they all work well. Performance was never my worry.
what is?
Vulkem is Trempro 626

If Trempro 635 is better than Vulkem, stop calling it by the name of an inferior product.
and once again...

desertair27 · 03-23-2012, 08:00 PM

Well now I have to try trempro 626!

Silvertwinkie · 03-23-2012, 09:21 PM

When I was at Airstream last way back when, I seem to recall them telling me that they use Acryl-R almost everywhere except for the wheel wells, where there, back then I think they used Vulkem.

desertair27 · 03-23-2012, 10:05 PM

Anyone have any tips for sealant removal? I've been spraying mineral spirits on the old nasty stuff(grey sealant of some kind) and letting it soak in for a while I go back and start scraping,once I get the loose sealant off I spray again and repeat. Lots of work!
There has to be an easier way!

perryg114 · 03-24-2012, 01:57 AM

62 Overlander

Personally, I think the Trempro 635 working time is a little long. The stuff tends to get stuff in it before it dries as it is. Other than for installing panels where you need long working times why would you want something that stays tacky for days. Parbond working time is a little too short. So maybe your Trempro 626 is better in 1% of the applications that the average user is going to be using it for. For sealing smaller jobs why do you need something that won't tack up right away? Nothing you have said about the 626 is making me want to use it and nothing I have read ether.

Perry

Frank's Trailer Works · 03-24-2012, 04:04 AM

I never told you to use it or anyone else. Use what ever you want. You can also call it anything you choose, I really do not care any longer.

wahoonc · 03-24-2012, 04:56 AM

Quote:

Originally Posted by desertair27

Anyone have any tips for sealant removal? I've been spraying mineral spirits on the old nasty stuff(grey sealant of some kind) and letting it soak in for a while I go back and start scraping,once I get the loose sealant off I spray again and repeat. Lots of work!
There has to be an easier way!

I use a heat gun (sparingly) and wooden scrapers. Orange sticks (ask a woman if you don't know) sharpened Popsicle sticks and tongue depressors are my weapons of choice. If you have silicone it is a whole different game.

Aaron

kevinb · 03-24-2012, 06:16 AM

Sandi and Bob
For larger areas like the awning I think sikaflex 721 would be your best bet,I understand it is currently used by airstream and is easy (easier) to work with than trempro and will clean up with soap and water. And it is uv resistant

Kevin

desertair27 · 03-24-2012, 07:15 AM

Quote:

Originally Posted by wahoonc

I use a heat gun (sparingly) and wooden scrapers. Orange sticks (ask a woman if you don't know) sharpened Popsicle sticks and tongue depressors are my weapons of choice. If you have silicone it is a whole different game.

Aaron

I just tried some silicone remover I got from VTS and it works surprisingly well.
I'll try some heat and the wooden scrapers.
Ghanks