Rails mold

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Rails mold

downunder
Hi guys,

back in my old country I remember buying some plastic rails for a sliding doors for ie a kitchen cabinet.

The plastic profile looks something like this:



Each sliding channel is about 5mm in width, about 1cm in height. This would be awesome cheap and quick method for a pre made rails mold.

Does this exist in AU?

thx
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Re: Rails mold

Kevnkite
Yep ,
you should be able to get it in any large Hardware store.Usually comes in white or brown.
(over on the East coast anyway ;~)
Kev.
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Re: Rails mold

downunder
Cheers mate!

Will check today.

On 2/1/14, Kevnkite [via BoardBuilders Forum]
<[hidden email]> wrote:

>
>
> Yep ,
> you should be able to get it in any large Hardware store.Usually comes in
> white or brown.
> (over on the East coast anyway ;~)
> Kev.
>
>
>
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> If you reply to this email, your message will be added to the discussion
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Re: Rails mold

downunder
Huh,  

not something easy to find or make...Everything available is bigger or smaller than 6mm (1/4"). Got aluminium profile which worked well, but still too big.

Now, I've routed a channels in a peace of wood, sealed wood with a sealer and will varnish it. In a hope that PU won't stick to it.

Routing a perspex is absolute nightmare. But one suggestion is to make a 6mm perspex strips and than glue this strips together on a smooth perspex side (not a cut side). A lot of work tho.

Third suggestion is to make a rubber mold. Hm. Need a "male" mold for that first. A lot of work too.

Router table would work a miracle here. But I do not have it:(

Any suggestion?
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Re: Rails mold

MBoards
A router table is fairly easy to make.
Made mine out of wood and PE leftovers from the rocker table.
I can post pictures later when i get home...

- Magnus
Ride Hard - Hang Loose
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Re: Rails mold

downunder
Done.

I've paid a price and swallowed it. Got the professionally made HDPE mold. Now we talking.

Now I can make 6 x 10(max) x 1700 mm rails. This means 2 rails per board, different colors per rail.

Will have some hopefully tomorrow:) Can't wait.
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Re: Rails mold

downunder
This post was updated on .
Absolute dream to work with!

This are my first PU pre made rails with fantastic finish on sides and bottom. The top is sanded anyway when placed in a core. You'll see.



I've made a first and last run with white colors. It's a pity I've made an error in measurements and can'Tt put two molds in the pressure chamber at once. Might fix it latter.

The PU goes off the mold like with no strength at all. Just like peeling off.

Cheers!

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Re: Rails mold

Chris
getting serious now!

Does it then harden up once heated during the main board cure?
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Re: Rails mold

downunder
Yes and no Chris

It is rock solid after 2 hrs, this one. Solid but flexible. That is a beauty of PU. You can machine it straight away.

As mentioned before, a PU can be heated, bent and stays that way.

The more I think of it looks like can be bonded with a core with any good glue (Titan III?). Saving some epoxy is better for my health as well.

D.
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Re: Rails mold

downunder
If ever experimenting with a PU in a pressure chamber, you might need to take into account this:



The slight curved finish after demolding. Not a big issue.
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Re: Rails mold

Chris
Do you not get that anyway with the PU shrinkage? or is the effect amplified because of the pressure cure? From some of the datasheets I've read on the stuff it's typical for 0.5-1mm in 1m shrinkage
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Re: Rails mold

downunder
The PU shrinkage in the middle I think comes due to surface tension.

But that is not a problem for a pre made rails which are slightly
higher anyway:)

On 2/16/14, Chris [via BoardBuilders Forum]
<[hidden email]> wrote:

>
>
> Do you not get that anyway with the PU shrinkage? or is the effect
> amplified
> because of the pressure cure? From some of the datasheets I've read on the
> stuff it's typical for 0.5-1mm in 1m shrinkage
>
>
>
> _______________________________________________
> If you reply to this email, your message will be added to the discussion
> below:
> http://boardbuilders-forum.1077691.n5.nabble.com/Rails-mold-tp1315p1346.html
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Re: Rails mold

Chris
I've lost the link now but just read that if you pour the PU into a heated mould you don't get the miniscous
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Re: Rails mold

downunder
A peace of warning:

the HDPE mold is distorting with a heat. Not only that, when HDPE is machined like this mold was, it will bend and distort.

The solution for this might be to secure your HDPE mold with a metal rods or something or make a mold of aluminium. Wood is no good as well coz of the heat when curing a PU.

Good luck.

D.
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Re: Rails mold

Chris
Thanks for the info, what size is your mould and does it make 6x6 or 6x3 rails?, how thick is the base of the mould?

I was thinking of getting something like 100x25 or or 100x30 but I can only get 1000 long without paying a fortune for it, then getting a 6x6 rail mould machined from that but then add another 6mm sheet on top of that fixed with locating lugs, that way I can wrap in vac bag and pull the PU through the mould with the vacuum pump
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Re: Rails mold

downunder
As you can see on the above photo, it makes 4 rails. 45x15 with 5mm base (6x10mm max rails).

The pressure pipe is 60mm with the opening of 49mm. Can't find a bigger pipe.

Yes, a vac might help. It is really easy and fast to pour that in a mold with a syringe (50ml per rail) tho.

Alu mold might be better or already avail and cheap as an "U" profile. Just can't find 1/4" inside dimension...
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Re: Rails mold

LeoEmi
Hey Downunder!! How are you guys? After a long time I'm happily back on the shop, even though I haven't been working I've been reading most of your progress, now back on the shop I'm having problems with the rails...again... hahaha. I read your post on PU rails ¿are you still using the same PU? PMC-790? why you finally decide to pre-made it instead of pouring it directly into the wood core channels? is it because it will foam or because it won't bond properly to the wood? about the foaming ¿over what wood have you tried it? I guess that as lesser porous the wood is then the lesser the foaming will be... I'm can't help to see that Cabrinha's factory video and try to duplicate the results, it looks so easy...
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Re: Rails mold

downunder
This post was updated on .
Hi Leandro

yes, the time goes really fast when the wind is on :)
The 790 is a PU rubber, and we need a PU plastic (instead of ie abs). I've got enough rails for quite a few boards now so not the issue for me any more. That is the main reason, I pre made whatever I can.
In theory, if everything is pre made you just assemble all the parts, process is well defined and less room for error (no foaming, etc).
So yeah, not to worry about bits and pieces saves time and it cheaper at the end.

You might have a look at my vid here about the rails:

http://shop.shinai.co/?product=pu-board-rails


Cheers

D.
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Re: Rails mold

LeoEmi
I understand you, but since I have to start almost from scratch right now I'm in a different position, I have to build molds and the pressure chamber... or try to pour the rails directly on the wood channels; two different pads and I'm not convinced on which should I take hahah, I feel seduced to try to pour it directly on the wood, I think that using vacuum to fill it and the using the same line to give it a little air pressure the foaming could be managed (about this I should run some scale test trials) but my main concern about this is if it will bond properly with the wood ¿what do you think?. By the way ¿how do you get the colour? the only plastic PU that I can get is white ¡¡your colours rocks!!!!! and the one you made that glows looks really cool. Every year since three or four years with some friends we organize a "night sail", it's like a kind of a celebration for the season, so in December or January you can catch up nice winds on nights with full moon, your glowing rails on that nights could be really awesome!! and very useful too.
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Re: Rails mold

downunder
Pouring the PU is always on a sealed wood with epoxy. You do not get
much foaming if is well sealed. But the bond than depends on epoxy ->
PU. However, some moisture, it might foam and ruin the core with a
huge air bubble.
Than you need to sand of the excess anyway. Now, imagine if your pre
made rails are in perfect size for your core. No excess, no sanding!
Easy. I still need to sand my rails, but that takes 5-10mins.
The PU is colored with a PU pigment. Not all pu will work with it.
Thanks, I did ride at night as well.

D.

On 11/23/14, LeoEmi [via BoardBuilders Forum]
<[hidden email]> wrote:

>
>
> I understand you, but since I have to start almost from scratch right now
> I'm
> in a different position, I have to build molds and the pressure chamber...
> or try to pour the rails directly on the wood channels; two different pads
> and I'm not convinced on which should I take hahah, I feel seduced to try
> to
> pour it directly on the wood, I think that using vacuum to fill it and the
> using the same line to give it a little air pressure the foaming could be
> managed (about this I should run some scale test trials) but my main
> concern
> about this is if it will bond properly with the wood ¿what do you think?.
> By
> the way ¿how do you get the colour? the only plastic PU that I can get is
> white ¡¡your colours rocks!!!!! and the one you made that glows looks
> really
> cool. Every year since three or four years with some friends we organize a
> "night sail", it's like a kind of a celebration for the season, so in
> December or January you can catch up nice winds on nights with full moon,
> your glowing rails on that nights could be really awesome!! and very useful
> too.
>
>
>
> _______________________________________________
> If you reply to this email, your message will be added to the discussion
> below:
> http://boardbuilders-forum.1077691.n5.nabble.com/Rails-mold-tp1315p1591.html
>
> To unsubscribe from Rails mold, visit
>
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