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Caulk Recommendations

One of my tasks to complete this summer is to remove and replace the caulk that seals the trim pieces along the length of the coach.

Is there a "best" caulk for this application?  Budget constraints are a consideration, but I will spend what is necessary if warranted.

Thanks in advance.
1998 U320 40'
2005 GMC Yukon
MC# 17609

Re: Caulk Recommendations

Reply #1 –
I would probably use the 3m 4200, here is a chart.
https://www.jamestowndistributors.com/userportal/document.do?docId=510

John
John and Stacey Smith
Motorcade NO: 11973
1997 U295 CSGI 40'..Build No. 5036     
920 Watts on the roof..CAT Power w/fuel Inj. Programmer
2021 GMC Sierra AT4 1500
EX..2015 Jeep Wrangler Sahara
Ex 1990 U280 RSAI 36'..Build No. 3638

Re: Caulk Recommendations

Reply #2 –
Steve, I use M1 made by Chemtech, excellant adhesion.
johnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Caulk Recommendations

Reply #3 –
M1, Sikaflex, and 3M 4000 are caulks that are often recommended by more seasoned RV folks.  These adhere, and last a long time.  Stay away from silicone caulks like GE, DAP, etc.

3M 4000 was the only one readily available in our area, so that's what we went with.  The motorhome has been through some very serious storms and we've been very pleased with the results.  Wore nitrile gloves, dipped them in a bit of water and smoothed the final seam.  Nice results.

I can't speak for the M1 or Sikaflex, but the 4000 does not attract dirt and dust like other caulks.

If you plan to do something like replace marker lights, then another option is to purchase a good quality butyl tape and use that to bed the fixtures and screws.  There are different grades of butyl tape.

Chris

Re: Caulk Recommendations

Reply #4 –

Steve, use the 3M 4000 UV variant. It will last longer in sun exposed locations.
Available at Amazon.  Shop around, you might be able to find a lower price.

Amazon.com: 3M 06580 Marine Adhesive/Sealant Fast Cure 4000 UV, White / 1/10...

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Caulk Recommendations

Reply #5 –
Follow up questions.

What is recommended to clean up the recommended caulks?  Water?  or Acetone?

How many tubes, to do both sides? I know it depends, but is it a 2 tube job or five?

TIA
1998 U320 40'
2005 GMC Yukon
MC# 17609

Re: Caulk Recommendations

Reply #6 –
Here is the Data Sheet for 3M 4000 UV.

Cleanup with acetone or toluene (no nearby ignition source).  Do the cleanup before it cures. Acetone or toluene may take off paint on the trim parts.  Paint thinner might work for cleanup and won't usually take off the trim paint.  Test to be sure.

Probably figure two 10 oz tubes each side.  I am doing front and rear cap strips this summer and am planning on two for each end.  If you have a part of on unused tube wrap the end of the nozzle with an airtight tape like packaging tape.  It does a pretty good job of keeping it useful for quite awhile.  I always have a 3oz tube on hand for jobs on the road. 
Roger Engdahl and Susan Green
2001 U320 3610 #5879 (Home2) - 2014 Jeep Cherokee or 2018 F150
Hastings, MN

Re: Caulk Recommendations

Reply #7 –
Roger,

Thanks for mentioning 3M 4000's UV properties.  I made a mistake in my earlier post.  We used the 4000, and not the 4200 (I checked our supply), because of the UV rating.  3M 4000 still has very good holding power for bedding items.

Our U-320 is gelcoat.  Prior to application we cleaned the areas with denatured alcohol to remove residues, etc.  I also had acetone on hand for areas where silicone caulk had been used before.

We used two tubes.  Did the front cap band, five marker front marker lights, GPS and satellite radio patch antennas, and portions of the rear cap top band and side bands.

Chris

Re: Caulk Recommendations

Reply #8 –
I just resealed my roof and used MasterSeal NP1 by BASF at the recommendation of a contractor friend. I had water intrusion around the front interior light fixture and signs of moisture were showing on the roof carpet. I am not sure if anyone else has had experience with this product, but for now it seems to work well for now.

Originally, I went to the box stores and neither of them carried NP1. The associate in the paint department commented that NP1 was a very good product, although they did not carry it. I ended up purchasing a case from Contractor Supply in Lufkin because I didn't know if I would need one tube or a dozen. They were kind enough to tell me upfront that I could bring back any tubes that were not used for a full refund, which they honored.

It took about 2 1/2 tubes to do the roof, which included around the A/C units, luggage rack, ladder posts, shower skylight, kitchen exhaust, bathroom roof vent, TV antenna, air horns, antennas, satellite dome, and anything else I am forgetting. I kept a spare tube just in case, and was informed when I returned the portion of the case that I did not use that the shelf life is not indefinite and an unused tube is good for six months to a year. It is a white sealant and will likely discolor with U.V. exposure, but visibility of the applied areas is limited from the ground so I wasn't too concerned with discoloration on this specific project.

I believe I paid somewhere in the neighborhood of $5.50/tube. If anyone else has used this product on their coach, I would be interested to hear how well it has held up versus other comparable products. This project is already done for now but it is only a matter of time before another leak pops up.
Cody, Gretchen, Paul, and Benny
Lufkin, Texas USA
2004 42' U320 #6270 Bunk Coach - Current
1985 35' FTX ORED #2479 - Previous
2000 40' U320 #5665 WTFE - Previous
Motorcade #17797
2008 Jeep Wrangler Unlimited Rubicon AEV 392 HEMI toad
2012 Honda Odyssey EX-L toad

Re: Caulk Recommendations

Reply #9 –
If I was contemplating redoing the caulk on the side strips at the same time I would also remove the strips and maybe the side
panels and rust proof any metal in back of the panels.John Haygarth could add to this he is the master of panel removal.
96 U270 BUILD 4810
85 380SL
Drummonds TN.