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Thicker DIN gaskets? Some drips exist that I cannot seem to cure


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Like many stills our components are all connected by DIN fittings.  One or two of them are virtually impossible to get perfect seals at all temps. 

I cannot tighten the fittings any more than they already are, and suspect that if I just had washers slightly thicker that it would bridge whatever tiny gaps exist.

Anyone know how to find such gaskets?  I suppose worst case I can cut thin rings from silicon and put them into the gasket ring beneath the normal gasket.


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An old trick from my HVAC days was to wrap gaskets with PTFE tape, I have done this for a few clients to help seal up some connections that just didn't want to seal with regular gaskets.

PTFE is non-reactive so its safe to use.

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Scientific studies have shown that substances released from Teflon (PTFE) can cause obesity risk, insulin problems and thyroid cancer. In addition, Teflon threatens at least nine types of cells that regulate the body's immune system.

Use silicone o-rings.

The silicone must be "tin-based" (hardener). There are many options for two-component silicones with platinum or tin hardeners.

These are food-grade silicones, they withstand temperatures well (up to 350 Celsius) and have elasticity up to 500%. Alcohol resistant.

Google: SK-790

You can independently make (cast from liquid silicone) any gasket you need. The form can be made from children's plasticine 🙂 and an old gasket.

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Alex, that's good to know, I know its a standard for most plumbing in the US so its interesting to hear the side effects from it.

Sounds like silicone is the better way to go.

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2 hours ago, Kindred Spirits said:

Alex, that's good to know, I know its a standard for most plumbing in the US so its interesting to hear the side effects from it.

(PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and is a PFAS that has numerous applications. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938.

Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low electric polarizability of fluorine. PTFE has one of the lowest coefficients of friction of any solid.

From me:
Why is Teflon dangerous?

Under normal conditions, this material is safe, but when heated to temperatures above 200 ° C, PTFE begins to decompose, releasing toxic products that have carcinogenic properties. The most dangerous thermal decomposition product of Teflon is perfluoroisobutylene (C4F8), which is an extremely poisonous gas. In addition, perfluorooctanoic acid (PFOA, C-8) is used in the Teflon coating production process.

Getting into food during heat treatment, these substances contribute to the development of cancer. In addition, the substance leads to cell mutations, disorders of the immune system. The most vulnerable to the effects of substances released from Teflon are the thyroid and pancreas. These toxic substances can cause various hormonal disorders.

Teflon is one of the most highly hyped industrial products and has found use in both kitchen utensils, aerospace, textiles, heart valves, electronics and microwave popcorn bags. This product brings considerable income. However, manufacturers were told the need to reduce by 95% the production of PFOA acid (the main component of the non-stick coating) by 2010 and then systematically complete its production by 2015, writes the Italian "La Stampa".

PFOA, a key ingredient in non-stick and stain-resistant materials, has been linked to cancer and birth defects in animals. It is found in the blood of 95% of Americans, including pregnant women. It has also been found in the blood of marine organisms and polar bears in the Arctic. The US agency said it will continue to investigate the impact of this component on human health to see if additional measures are needed.

“Science is looking at all the qualities of PFOA, but there are concerns, and therefore minimizing the effects of using this substance is a completely fair decision both from an environmental and human health standpoint,” said Susan Hazen, EPA Deputy Head of Pesticides.

DuPont, one of the companies that received the complaint, said that research conducted by its experts and some independent scientists indicates that pans and other items made from its materials are quite reliable.

In addition, the company emphasized that so far nothing is known about the harmful effects of Pfoa on human health and so far they have not been able to find a worthy replacement for this chemical component in the production of Teflon, whose sales in 2004 brought them $ 1 billion. “We have been searching for 30 years without success,” the company said.

In the meantime: William Bailey III, born with multiple birth defects in 1981 while his mother Sue was working in a plant that used the substance, is suing DuPont seeking compensation for his injuries.

Yet eight Teflon-using companies agreed to the program: 3M/Dyneon Arkema, AGC Chemicals/Asahi Glass, Ciba Specialty Chemicals, Clariant, Daikin and Solvay Solexis.

Observers say the agency's decision is the most aggressive since it banned asbestos 15 years ago. Everyone understands that yesterday's statement is more of a recommendation than a ban. However, experts advise: "Get rid of scratched pans."

Teflon secretions are especially dangerous for children. Data from the US Environmental Protection Agency shows that DuPont has known since 1981 that mothers pass PTFE to their children and that it can cause facial deformities, which has been proven in animal experiments. In parallel, these substances can get everywhere. Mainly at risk are production workers and those living nearby. In 2001, residents living near a DuPont plant in the UK sued the company for knowingly polluting sewage. This was thought to be the reason for the increased incidence of prostate cancer and interference in women's reproductive functions in the area, as well as the spread of leukemia cases. The court ordered at least $107 million to be invested to reduce the amount of PTFE in wastewater and fund research on the effects of these substances on human health. These results could force the company to spend another $235 million on long-term health monitoring projects.

"Teflon" frying pan does not tolerate high temperatures, and therefore should be cooked on low or medium heat.
It is difficult to determine by eye that the dishes have heated up to the "correct" temperature, so they began to produce frying pans with a heat-sensitive indicator (thermospot).

A change in the brightness of the red circle in the center of the inner bottom indicates that the pan has reached 180 degrees and it is time to load food immediately, while continuing to monitor the temperature.


Silicone on tin and "silicone on platinum" - differences

If you delve a little into the topic of molding silicones for molds, you will find out that there are so-called tin silicones and platinum silicones. A person inexperienced in this topic will definitely have a question: What kind of silicone do I need and how does tin silicone differ from platinum silicone. Briefly read on.

Differences between tin and platinum silicone

1. Chemical composition. the main and key difference, which was reflected in the name of the material and “went to the people”, depends on the catalyst: Tin silicone has a tin-based catalyst, platinum silicone, respectively, has a platinum-based catalyst.

2. Mixing proportions. Silicone for molds is always supplied as part of ready-to-use kits - mixed and poured. But the order of mixing and proportions may differ. Tin silicone is a container with the base material and a small bottle of hardener, which is added to the silicone in the amount of 2% of the total weight of the silicone taken. Platinum silicone is a two-component material, supplied as a kit consisting of two balance buckets, kits are mixed 1 to 1.

  3. Color. The native color of silicones is also different. Tin is exceptionally white, but platinum is cloudy transparent. In any case, both of these silicones are easily tinted by weight with specialized dyes.

4. Shrinkage. Any molding material that, in its application, involves curing in one way or another shrinks (becomes smaller in volume) after curing. For tin silicone, shrinkage is negligible: about 0.05%, but for platinum silicone, it is practically absent altogether.

5. Temperature range of operation of the finished product. Tin cannot boast a wide temperature range of use: from -40 to 80 degrees Celsius. And platinum can: from -40 to 250 degrees.

6. Purpose of application. Despite the fact that both silicones copy the relief and texture of any object equally well, tin silicone is not subject to expert opinion, which allows the use of products made from it in contact with food. But platinum silicone has such a conclusion. Food containers, baking dishes, silicone food mats, etc. - all this can be made from silicone on a platinum catalyst.

  7. Platinum silicone, unlike tin silicone, is subject to inhibition: This means that the uncured mixture of platinum silicone, upon contact with certain materials and conditions, loses its properties, i.e., ceases to cure.

Here are the materials and conditions:
- Sulfur.
- Fresh rubber or latex.
- Amines.
- Alkyd varnishes.
- Polyester resins.
- Alcohols.
- Temperatures below 16 degrees Celsius.

This rule does not apply to finished products made of platinum silicone.

Secrets and recommendations in working with platinum-based silicone:

Before use, thoroughly mix components A and B in factory packaging. Experts recommend treating the master model with a release agent.

Mix the required amount of components A and B, in proportions of 1 g of component “A” and 1 g of component “B”. The resulting mixture must be slowly stirred for 4-7 minutes. It is important to thoroughly mix the mixture in places near the bottom of the container and its walls!

Before pouring, you can degas the composition in a vacuum chamber, ridding it of air. Fill the material, preferably pour the mixture at one point. Allow time for the silicone to fill the space of the master model, pouring at least 1.5 cm from the highest point of the surface of the master model.

Leave the material to harden for 6-12 hours at a temperature of 23°C, protecting the filling from dust and dirt.

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