Shopsmith Forums

Butyl tape may be used for a lot of different things but I use it as a weather seal around the windows in my RV.

It really is not just a putty that is intended to be crammed into a hole to close it up. It is more of a gasket that should be placed between two surfaces (I think metal) and then squeezed tight to form the seal. It works and works well.

BUT, I get frustrated when using it. When the pressure as applied, some of that butyl squeezes out and looks terrible. It can be trimmed off with a plastic credit card or a putty knife but then it looks like it has been "cut off".

This looks better that before it was trimmed but it does not look like a professional job. It looks like "cut off squeeze out".

I am hoping that someone has a suggestion or two or three on how to give that squeeze out a professionally finished look. I have seven sets of windows on my RV that are all going to have to be resealed and I would like for them to appear to have been done by someone who knew how. I need help.

Please do not suggest a silicone seal. I do an even worse job with that stuff and the nasty results seem to linger for ever.

I know that silicone does a good job. I can see that in a glass shower stall that is in my bathroom but I can't do what that installe did. I don't know why. I watched him closely when the shower was installed but I did not see any trade secrets. Eveb after watching him, I still have silicone all over places where it does not belong.

Is it possible to use a wet finger to smooth it out?
I've never used it, so I'm just guessing.
I'm with you re: silicone. A razor knife works, but I'm not skilled enough to make it look really good.

dusty wrote:Butyl tape may be used for a lot of different things but I use it as a weather seal around the windows in my RV.

It really is not just a putty that is intended to be crammed into a hole to close it up. It is more of a gasket that should be placed between two surfaces (I think metal) and then squeezed tight to form the seal. It works and works well.

BUT, I get frustrated when using it. When the pressure as applied, some of that butyl squeezes out and looks terrible. It can be trimmed off with a plastic credit card or a putty knife but then it looks like it has been "cut off".

This looks better that before it was trimmed but it does not look like a professional job. It looks like "cut off squeeze out".

I am hoping that someone has a suggestion or two or three on how to give that squeeze out a professionally finished look. I have seven sets of windows on my RV that are all going to have to be resealed and I would like for them to appear to have been done by someone who knew how. I need help.

Please do not suggest a silicone seal. I do an even worse job with that stuff and the nasty results seem to linger for ever.

I know that silicone does a good job. I can see that in a glass shower stall that is in my bathroom but I can't do what that installed did. I don't know why. I watched him closely when the shower was installed but I did not see any trade secrets. Eveb after watching him, I still have silicone all over places where it does not belong.

Not addressing the butyl tape, but tube applied sealants. I have not used the tape, but in my current state of ignorance, think that after applying it even with the outer edges, that applying the 'squeeze' pressure at the edges first and 'rolling' the parts might cause the squeeze out to travel inward rather than outward. Orrrr leaving a gap at the edges to be 'filled' by the squeeze out.

I have recently received instruction/advice from a professional caulker(crack sealer) on the how to of applying caulking. He also gave me an older set of spatulas that he had replaced with a new set.

Contrary to my previous misunderstanding of how to do it, I learned from him there are 4 steps to getting a good 'fill' both in effectiveness and appearance.

1) Fill the crack with caulking by using the 'gun' in push mode. That is, the advancing gun is pushing the caulk into the crack as it advances(not the tip as it passes over the caulk). Try to get just slightly more than the amount needed applied. The result will be varied (uneven).

2) Using a spatula(spatula defined/described below) that is sized for the 'current task' again in push mode(the round end advanced into the bead just applied) at a shallow angle. This removes excess caulking and is wiped off the spatula or allowed to roll off the sides of the spatula. This creates a straight boundary on both sides of the caulking(assuming straight sides of the surfaces being caulked but at least a consistent fill[assuming push consistent 'angle'] amount between them if not). If a vertical joint, advance from bottom to top.

3) While holding the spatula at a steeper angle but now in 'pull' mode and pressing tight to both 'sides'. dress the joint(smooth it out). There should be little to no squeeze out if steeper angle is 'proper' compared to the earlier shallow angle during excess removal. If a vertical joint, this should be advanced from the bottom towards the top.*

4) Repeat 3, but this time in the opposite direction. *The vertical joint looks better if done top to bottom last.


A spatula for this endeavor is a thin, narrow, long stainless steel 'blade' with a rounded business end. They come in different sizes for different sized joints. They are similar to a wooden popsicle stick and I have seen the popsicle sticks sold for use as caulking spatulas. I have not tried the popsicle sticks but believe they are too thick to perform step 2 effectively.

I have done these steps as described and have discovered there is still some 'skill' involved, but with not too much experience/practice very acceptable results are attainable.

Much more acceptable than previous method of applying, then smooshing with a moistened finger!]21299[/ATTACH]

I think the secret to these spatulas is the rounded end and the thinness. Any thing similarly shaped(and thin) should work. The round end is a semicircle with a 'semi' diameter equal to the width of the spatula. The sizes above are the 'blade' width.

And yes the spatulas flex while being used. That makes them controlling the 'tension'.

My answer is that you will not get a professional result with butyl tape (or silicone) because that's not the material a professional would use.

I use neoprene as the gasket between the window frame and the body. I use a rubber channel around the glass itself. That's how everything comes from the factory these days, and both are available in bulk lengths at larger auto supply stores (NAPA seems to have the best selection) or over the internet. Both are simple and clean to install.

I did auto glass a thousand years ago, and yes butyl tape was used by pros, but I'm not sure if we are talking about the same type, so I will give you a step by tep description of what I remember doing.
Clean the metal and glass surface that will be facing each other
Prime with a primer made for butyl tape
Put the right size ruber spacers in the body opening for the glass to rest on
Put the tape on the glass, this is the hard part ( I think) the tape has to be stretched as you lay it down on the glass just a little and should be an EVEN thickness all the way around
Lay a bead of bytyl caulk around the outer edge of the body opening
Press the glass firmly in place with out squeezing out the tape, or the caulk
Place more caulk around the outer edge of the glass in the opening
Snap the trim back in place.
I hope this helps you.

Edited to add: I dont think you are comparing apples and aplles, it seems to me your asking for help from someone in the building trades, and should be seeking advice from someone in the auto/RV trade

A friend of mine uses what he calls rope caulk on his RV, said it was the easiest and best.

I think Dusty is requesting help 'period'. Any/all sources welcome!

[quote="JPG40504"]I think Dusty is requesting help 'period'. ]

Advise is always welcome, no matter from whence it comes. I learned a long time ago to listen and learn from those who have experienced the "school of knocks".