Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: RipSlider on May 15, 2008, 03:19:55 pm

Title: Is there such a thing as "flexible epoxy"?
Post by: RipSlider on May 15, 2008, 03:19:55 pm
Hello all.

I'm trying to find an expoxy glue which is a little bit flexible.

Normal expoxy glue is very brittle and tough. My current build is a wave piecing boat and the hull will be flexing and bending a good amount.

What I'm looking for is an epoxy that has a bit of "give" it it - is a little bit rubbery - so that the boat doesn't pull itself to bits.

Anyone have any idea's on if such a thing exists?

Thanks
Steve
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Colin Bishop on May 15, 2008, 03:34:39 pm
Not sure about Epoxies but sounds like what you might need is Evostick "Serious Stuff" which does set slightly rubbery.
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: J.beazley on May 15, 2008, 04:07:02 pm
Good call Colin, Evostick is good like that.
The other option is bathroom sealant it sets hard and has got a bit of give to it unlike silicone.

Jay
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Colin Bishop on May 15, 2008, 04:46:44 pm
There are also marine sealants like Sikaflex which are good, but quite expensive. http://www.ship-technology.com/contractors/sealants/sika/
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Faraday's Cage on May 15, 2008, 07:25:20 pm
Quote
Evostick "Serious Stuff"

Colin, I think you mean "Serious Glue". Im on my 3rd tube, excellent product which does remain slightly flexible and is waterproof.

FC
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: tigertiger on May 16, 2008, 02:55:58 am
Hi Ripslider

A question for you. Why are you asking, exactly?

Is this becuase you are looking for a plastic agent to be reinforced with you carbon fibre?
Or to use at the joints of the components?

Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Captain Jack on May 16, 2008, 03:05:20 am
http://epoxy.dow.com/epoxy/products/prod/flex.htm
Don't know if you can get these products in the UK, but here's some awesome stuff.
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: andygh on May 16, 2008, 03:08:55 am
http://cgi.ebay.co.uk/FLEX-EPOXY-EXTRA-STRONG-GLUE-WELD-PLASTIC-MADE-in-UK_W0QQitemZ360050034807QQihZ023QQcategoryZ19168QQtcZphotoQQcmdZViewItem (http://cgi.ebay.co.uk/FLEX-EPOXY-EXTRA-STRONG-GLUE-WELD-PLASTIC-MADE-in-UK_W0QQitemZ360050034807QQihZ023QQcategoryZ19168QQtcZphotoQQcmdZViewItem)
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Colin Bishop on May 16, 2008, 08:50:31 am
Evostik make Serious Glue and Serious Stuff - rather depends on what you want to do. http://www.tooled-up.com/ManProduct.asp?PID=132254&MAN=Bostik-Serious-Stuff-Weatherproof-Adhesive
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Faraday's Cage on May 16, 2008, 09:22:38 am
Apologies Colin, didn't realise that there was a similar named product out there.  :embarrassed:

FC
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: Colin Bishop on May 16, 2008, 09:32:36 am
I suspect they are basically the same FC. The glue for conventional glueing and the other one for bigger surface "quick grab" purposes. In this case the one you mentioned would probably be the best one to use. Both sold in Homebase I think.

Colin
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: nightowl2912 on May 16, 2008, 08:21:06 pm
Hi all,
How about mounting small rubber blocks in the hull
and then mount the hardware on to the blocks

Andy
Title: Re: Is there such a thing as "flexible epoxy"?
Post by: StarLocAdhesives/FiveStar on May 22, 2008, 11:29:36 pm
http://cgi.ebay.co.uk/FLEX-EPOXY-EXTRA-STRONG-GLUE-WELD-PLASTIC-MADE-in-UK_W0QQitemZ360050034807QQihZ023QQcategoryZ19168QQtcZphotoQQcmdZViewItem (http://cgi.ebay.co.uk/FLEX-EPOXY-EXTRA-STRONG-GLUE-WELD-PLASTIC-MADE-in-UK_W0QQitemZ360050034807QQihZ023QQcategoryZ19168QQtcZphotoQQcmdZViewItem)

Unlike a standard epoxy this has rubber in it so it is not brittle, absorbs impacts and has far greater sheer strength, so is very good on areas needng extra strength,

however all our standard epoxys (unlike 99% of the ones you can buy in the general market) contain a rubber toughener , so are far less brittle than other epoxys, the FlexEpoxy contains an extra 2 types of rubber meaning it is flexible, instead of toughened like our standard range, but i think you dont want a flexible one, just a toughened one such as our standard range of clear toughened resins

http://epoxy.dow.com/epoxy/products/prod/flex.htm
Don't know if you can get these products in the UK, but here's some awesome stuff.

None of the ones listed on that link by dow are suitable for use as is, they are components to formulate epoxy products with , they are only used as trace components with a base epoxy resin to improve its toughness

Nowdays as well as the trace resins, a flexible or toughened epoxy contains an adduct of epoxy resin and ctbn rubber, basicaly we buy ctbn rubber , mix in the right ratio with epoxy , add a combination of catylists and heat them, when the reaction has happened we end up with a different epoxy, a reactive rubber/epoxy chain of

epoxy- nitrile rubber(ctbn)- epoxy

when set its epoxy-ctbn-epoxy-epoxy-ctbn-epoxy-epoxy......

The aditives listed by dow are used to give specific properties , we use some similar additives (not from dow) to add slight flexibility, but they are only at about 2-3% of the total epoxy

the epoxy will set as a standard epoxy does, but is joined by the ctbn rubber to give high flexibility, at this point usless as an adhesive as its too soft, so it is diluted down to the correct ratio with a blend of unreacted epoxy resins to give the required hardness and flexibility

Once set the epoxy should not appear to be flexible normaly, it will just absorb impacts and have great shear strength, so not actualy flexible so refered to as toughened resins unless high levels of rubber are used


For extra strength on wood planking and things like that you should only need the standard range,
the FlexEpoxy is more for use on areas that will be geting bent such as car bumper repairs etc