Gluing pvc trim to douglas fir

[Chuck Keysor]

Hello Shopbot Friends! What type of glue do I need to attach decorative PVC trim (18" long, 3/4" wide x 1/2" thick) to the 1" thick edge of 2 inch wide douglas fir boards? This is for an outside porch railing, which will all be painted.

When I have used PVC before, I usually attach it to PVC. So PVC glue is pretty obvious. But one time, I made up long pieces of 3/8" thick by 3/4" wide trim pieces and nailed them to wood for decorative parts of a porch. I only used little brads, fearing that the PVC may try to move more than the wood, the glue bond would fail. So I didn't want to glue it to the wood. But that fine trim attached with only brads was simply too weak, and some of it was damaged by kids playing on the porch.

So on this project, I do want to glue the PVC on solidly to the wood for long term durability. Is this OK? Or will the PVC pop off of the wood because it expands differently than the wood to which it is glued? If gluing is OK, what type of glue should I use????

Thanks, Chuck

PS: I undertook this project in part to get practice with my Shopbot. But it turns out in making about 25' of complicted railings, that the Shopbot time is just a tiny portion of the project!

[genek]

Mr Keysor the pvc and the wood will expand differently the pvc will expand and contract with heat and cold. The wood will expand and contract with the humidity of the wood. Why not do a round over on the edge this softens the edge and looks good. I know you want to protect the wood, but in a few years the pvc will crack on its oWn around the nails. This is my thoughts. If you are going to glue would use a gorilla glue or silicone that way it will give some.

[NSC3d]

Have you looked at at long set epoxy like gflex by west system?
Its designed for bonding plastics.
Its expensive so i don't know how much you need but surface prep is key in a lasting bond with these types of materials heat and pressure also key to make it stay a long time.
Other long set marine epoxy like hardman and a few others are good products.
It will be very important to make sure the paint stays and water doesn't get in as any bond will be broken by the onset of moister in the wood.
I would definitely consider using additional mechanical fasteners to back up the glue job, maybe bigger brads, like you suggested.

[sam_harbold]

Here is what we use all the time. http://www.bondfill.com/bond-and-fill-structural

Sam

[Chuck Keysor]

Thanks for the replies so far.......... I have been slow to reply because my PC with Photoshop died, and Adobe won't let me re-install my old software into a new computer.... Anyway, I can't post a picture of what I am doing, which would clarify things, maybe.....

After the feedback so far, I am leaning towards remaking all of these trim pieces out of wood to avoid possible future problems...... After I can figure out how to cut the size of my pictures down, I will post them.....

Thanks, Chuck

[genek]

thanks for the replies so far.......... I have been slow to reply because my pc with photoshop died, and adobe won't let me re-install my old software into a new computer.... Anyway, i can't post a picture of what i am doing, which would clarify things, maybe.....

After the feedback so far, i am leaning towards remaking all of these trim pieces out of wood to avoid possible future problems...... After i can figure out how to cut the size of my pictures down, i will post them.....

Thanks, chuck


chuck if you want e-mail it to me will adjust it for you. And send it back or post it for you.

[Chuck Keysor]

Thank you Eugene for your offer! Just a few moments ago, I sent you an email with three pictures attached.

When the pictures are posted: The first picture shows the short section of railing. Another section is about 6 feet long, and the other is about 14 feet long. Each railing section is supported by posts at each end, and 3 inch blocks to hold the middle sections up from the porch floor (by 3 inches.....) In that picture, I had not yet made the PVC trim parts that are the subject of this thread. The next two photos show the PVC trim parts installed.

I think I had to make about 100 of these little PVC trim pieces in order to get the 74 good ones I needed. I used up more than a 1" x 6" x 8' PVC trim board to make these parts. I don't want to throw these away if I don't need to. But I don't want to use them if it is likely that they will not last, or pop out. So some sound/valid input is needed.

Now, why did I use PVC in the first place????? Originally, I was going to make the wooden arch on my shopbot, without the molding detail. Instead, the molding detail was going to be made out of PVC, and applied from the bottom of the rail opening, straight up, and then wrap around the underside of the arch. Hence I had the need to be able to bend the molding detail, and my decision to use PVC seemed simple.

But for some reason, I said, wait, I ought to be able to carve the arch, with the molding detail as part of the arch. So I did that. But I had already purchased the PVC, and since I had lost the receipt, I figured I may as well use it.

This turned out to be a fateful decision! That is because on almost every arch, the molding detail ran against the grain, and raised fuzzy garbage. I spent more time trying to clean up the fuzzy garbage then I did in all the rest of the surface prep. I spent hours and hours trying to clean up these arches so they would be usable. Most of that would have been avoided had I followed my original plan, as there were no fuzzies on the PVC to clean up...... Sigh

So again, seasoned, experientially based input would be appreciated, thanks, Chuck

PS/Note: The proportions of the railing are a bit odd, because my City's code requires the railing to be no less than 36" high (which is what I used) and no opening can be wider than 4". So this made my rows of Gothic arches look more like rows of missles. I would have used very different proportions if Code would not be so sacred in my city. Too bad you can't fight City Hall.........

[Chuck Keysor]

Eugene, I just got this email message in reply to the email I sent to you with the three attached photos (Each photo was I think 1.5meg.)


"Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out."

Now what? Chuck

[genek]

Eugene, I just got this email message in reply to the email I sent to you with the three attached photos (Each photo was I think 1.5meg.)


"Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out."

Now what? Chuck

did you send it to eking1953@yahoo.com

did not get it.. and my message box is no where near full.

[bleeth]

Chuck:
I use elements but I think the system is the same in Photoshop (if you get it operating again-a contact with Adobe should get that straightened out).
Open the shot in photoshop,
Save AS with a new name (I would use somehing like trim 1 adjusted) and select jpg.
You should get a dialogue box that allows you to lower resolution. Lower resolution. The nice thing about doing it this way is it doesn't reduce the overall size of the picture but does reduce pixel size, which is what the forum likes-lower pixels.

[genek]

Here is Mr. Keysor's Photo's I was out to doctors appointments today.. sorry for the delay... Now you can see What Mr. Keysor's is talking about by the great work.

[Chuck Keysor]

Thank you Eugene. I hope the pictures will spur some added input on my PVC to wood question.

As to Photoshop, my 7 year old Creative Suite 2 could not be updated or reactivated. So I had to buy a new Creative Suite 6.... Ouch!$$$$$$$$

Adobe site says Creative Suite 6 will be the last they issue on disks. After that, their products will only be available on "the cloud". This is a terrible situation from my point of view. If you want to have your own disks, and not pay monthly or annual fees, check this out, and maybe you should hurry up and buy CS6.

Thanks, Chuck