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Where to buy THF by Dupont?

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Q. Hello. I have been reading on this site how to paint uPVC and make the paint stick. One of the answers was to get THF (tetrahydrocarbon^tetrahydrofuran) by Dupont, mix some colourant into it and 'bobs yer uncle'. That's all well and good but where would I source some THF, etc.

Robin Adeleted
hobbyist - Southampton, Hampshire, England
outdated


First of two simultaneous responses -- +++++

A. Robin,

THF ... simple, Sir ... goest thou to your local hobby shop and get some PVC primer ... now, said shop might well not have a clear primer because ... over here, anyway, the primer is coloured blue so that the plumbing inspectors can see if someone has done a proper job of 'cementing' pipe and used the 'primer' (pure or pure-ish Tetrahydrofuran) first of all prior to cementing.

Caution ... don't do this in the kitchen! There's quite a smell from THF. Apply in a well ventilated spot.

An idea ... try out some ABS solvent ... this is not so potent as THF but it might be OK to get a bond and also would not cost so much ... it's called MEK.

Happy painting.

freeman newton portrait Freeman Newton
- White Rock, British Columbia, Canada
freeman newton died


Second of two simultaneous responses -- +++++

A. On this side of the pond, THF is tetrahydrofuran. It is a very strong solvent of PVC and shows up in many PVC cements. It can also be used as a softener of several vinyls. Trying to find it in small quantities may be difficult. If all else fails, you might try some of the scientific supply houses. It will be a lot more expensive than if you can find it in small quantities from a chemical supply house or a paint store.

James Watts
- Navarre, Florida


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A. First of all THF is known as tetrahydrofuran and is a horrible smelly organic solvent. Secondly, it is sold with an additive in it to prevent to formation of explosive peroxides, so be very careful when you use it. It may be possible to buy it from a chemical supply house (e.g., Aldrich or VWR International) or a specialist hobby shop. You can also use other solvents for PVC, such as MEK / methyl ethyl ketoneamazoninfo. This is much safer and nowhere near as smelly. Again, you will need a supply house or specialist hobby shop. However, you may be able to get some from a local chemical company.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


March 7, 2008

Methyl ethyl ketone (butanone) is readily available in gallon quantities in just about any hardware store.

In the US at least.

Jake Johnson
- LR, Arkansas


March 2, 2012

Q. I have a question that is related to this subject.
My problem. Two pieces of PVC pipe were glued together and I need to pull the female portion of the PVC out. The female portion can be discarded however, the male portion of the pipe needs to be separated and be brought back to as pristine condition as possible so it can be used again.

Can I use MEK or another solvent to dissolve the inner male portion of the PVC (carefully) without damaging the outer female portion?

Cutting it and splicing together is not an option, the female PVC is part of a larger item that will need to be used again.

thanks in advance!

Sam

Sam Worth
- Rowlett, Texas, USA


March 6, 2012

Hi. Sam.

These pieces were joined by "solvent welding", not "gluing". Please take a minute to clear your mind of the image of two separate fittings glued together, and think in terms of a single new piece. The only way to separate them may be to machine away what you no longer want; I'm not sure.

In one paragraph you say you can discard the female portion but must save the male portion; in the next you say you want to dissolve the male portion but must not damage the female portion, so please clarify :-)

Luck and Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



May 3, 2013

Q. Hi,
I am doing solvent bonding with THF to join TPU sheet material.
I get fair results if I spray and allow dwell time, re-spray and clamp under pressure.
Someone told me they wetted it really quick and rolled it with a rolling pin; I tried that and got poor results.
I seems that the THF causes uneven surface height because the THF attacks the surface and melts it.
I was using the smooth side of the material versus the matte side ... which may work better?
The THF dissolves extremely quick, is there an additive or a better solvent to bond with?
Thanks,

Dennis Schreuer
- Palm Desert, California, United States
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