Heat shrink instead of vacuum grease?

Hi everyone.

I’ve been reading the treads about which is the best vacuum grease etc, loads of great info so thanks. I noticed a lot of you were saying to use pre made PTFE sleeves instead of grease to avoid any contamination. I like this idea but I’m in the UK and I can’t find them anywhere, I can import them but the cost is crazy.

So I’m going to do an experiment with some PTFE heat shrink/sleeves. The same stuff that is used to insulated electrical cables. I can get them in the perfect size to just slip over and using a heat gun, shrink them to pretty much any joint size. The temperature range is -70 to 260C so I don’t see any problems.

This is for my SPD set up so I’ll do a test to see how well it holds vacuum and post some pics if anyone is interested.

This is the stuff by the way: HPTF Clear Teflon/PTFE Heat Shrink Sleeving in Various I/D sizes and Pack Qtys | eBay


Nice report back
Thou there must be some compound other than ptfe to give it. This function

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I will do. People say to rub hot distill on the joints as well. Do they mean that literally? Take some crude or something and use that as grease?

Not crude distillate yes that works also
But I guess you have to make some first :grin:


Chicken and egg situation. I’ll figure it out. Waiting for my vac gauge to come, then I’ll do some experiments. :crossed_fingers:

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Use grease, sleeves are for bad glass that doesn’t have plumb joints. If you have to use sleeves then that says something about the quality and safety of your hardware, Wich isn’t good.


On the contrary, I find grease is a potential contaminate and is not very hygienic to use with a product that is intended to smoke.Ptfe sleeves have three good things going, first they can provide a grease free seal, they also prevent ground glass joints from seizing, and will provide extra sealing ability if your glass happens to have some wonky joints.All three of these factors add up to a better product than just grease.There have been multiple threads I have read where people have contaminated their product with vacuum grease, imagine how many liters of potentially contaminated distillate was produced like this with the operator being totally ignorant to this fact.


What makes the PTFE sleeves bad for glass joints? Can how can it damage them? I’m more inclined to agree with @Soxhlet, I’m more interested in avoiding contamination. But I’m still learning so why do you think/ how do you know that the sleeves are bad?

I think @spdking is saying that PTFE sleeves are more useful on lower quality glass where you might not get a full seal using grease because of the quality of the glass. IMO grease can be used without contamination, and even if you are worried about contamination, there are work arounds such as using distillate instead of grease on joints you think might cause contamination.

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I am using cheap-ish glass so. It’s just to experiment anyway and seeing as though there doesn’t seem to be a way to figure out the best grease for what I’m doing I thought it’s worth a shot.

I will use distillate too…When I have some.


I suppose contamination and application then would be user error.

We carry fda certified grease for the guys who ask for it.

We have tested out glass down to 11 scale and regularly hold then at 7/8 scale in the shop as demos for our connections.

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Contamination is purely a ignorance and laziness issue.

It’s very easy to keep your workspace clean and not overly apply grease. Remember when applied right grease only covers the upper 1/3 of the widest part of the joint. Factually speaking if grease gets in your batch you are mis using it.


That’s interesting, good to know thanks. So as long as you don’t apply too much it’s not going to make its way down the joint into the material.

But how can PTFE damage the glass? They both sound like good options. While I’m learning/practicing, I thought that eliminating the possibility of contamination would be one less thing to worry about. Then introduce grease if I need to once I’m comfortable with the set up and process etc.

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I don’t think it’s damaging persay. It’s just not the right tool for the job. Users find this as a band aid, and not a solution to the actual leak. The issue with leakage has more to do with glass, quality, safety etc…and ability of the glass to perform. The issue with ptfe sleeves is the has PTFE memory. So they become less effective Everytime you use them


I hope I don’t offend anyone when I say this(I must not forget this is future4200 site full of weirdos)…

Anyone who accepts leaky glass that then requires Teflon parts or shrink wrap to seal thier joints really is digging at bottom of the barrel quality when buying thier hardware. And accepting garbage at thier door step in a effort to make it okay by using these products to bandaid the issue instead of solving it isn’t a good thing.

Really you shouldnt have any of these issues and it’s a sign of mis use and poor quality.


Nothing wrong with being weird.

I get what you’re saying. I haven’t even tested my full set up yet, so I started the topic because finding vac grease in the UK without having to spend loads of money is quite difficult. So I thought I’d try with the PTFE first.

My concern, as is the concern of many weirdos (as you call us), is that even if you are only covering ‘the top 1/3 of the widest part’ you are still diffusing grease into your system.

It may not be a lot, but the reason they call it “incidental product contact” is because you don’t put it into your product on purpose—it will leach periodically and there is basically no way to tell when you’ve got residual vac grease in your product…

From a compliance perspective (from a Pharma quality outlook) if you cannot demonstrate that the grease you use is NOT contaminating product, it will be assumed that it IS contaminating product.

PTFE is a good work around…if you have to replace it every time, so be it.

@spdking @Soxhlet do you guys have any evidence to suggest PTFE doesn’t seal as well as grease?


This is not true at all, we have a helium leak detector and I can show you pump down curves, ratings, and leak rates in person if you want. The greases initially gas off after assembly but you aren’t breaking it down via vacuum

You are thinking of basic siilcone grease like Dow Corning. Wich is the cheapest and shittiest grease out there. It will hold at 40-50c right above a few microns in reality. There are greases that will hold 8-11 scale vacuum at 250-300c. There’s a big performance difference.

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Yes I do have proof it’s called helium leak detections.

Again. As for a pharma and scientific basis grease is not getting in your batch when used right. And it’s been written most processes and for compliance that correct greases are to be used and observed thier fail point in a effort to have correct application protocol.

If you have grease getting in your batch you clearly are mis using it and or using wrong type of grease. They make different greases so people are comfortable using them. I have a few certified fda grease we sell but do not advertise, and I have forms of appiezon.

I’m not quite sure you understand what your saying when you make claims like “you are diffusing grease into your system” or “you cannot demonstrate that grease is not contaminating your system”. On the contrary - I can prove and demonstrate everything you said was a opinion, and not factually and can show you otherwise. You cannot support these claims becusee they are not scientific but rather your experiences and what it took for your success.

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