Gluing Delrin to wood

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NGLJ

NGLJ

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Surrey BC, Canada
Since Delrin drills and threads very nicely, I am trying it for the dowel inserts for kitless using wood. I am having mixed success in gluing the dowels into the wood. I have tried CA and polyurethane, but not epoxy so far. Even with roughening the Delrin sometimes both work, and sometimes they don't. Is epoxy the answer or is there something which is specific to Delrin that I should use? I have looked online and seen various suggestions, a Locktite product for example. Personal experience is the best recommendation.
 
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Delrin is tough stuff to glue to anything as I believe it is designed that way. I did a search on Google for, "How to glue Delrin" and came up with quite a few hits. Mostly they say anything that heats as it cures works well. There are some specialty adhesive also listed.
Do your self a favor and type that question into a search engine.
 
From Wikipedia:

Polyoxymethylene (POM), also known as acetal,[4] polyacetal, and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. Short-chained POM (chain length between 8 and 100 repeating units) is also better known as paraformaldehyde (PFA). As with many other synthetic polymers, polyoxymethylenes are produced by different chemical firms with slightly different formulas and sold as Delrin, Kocetal, Ultraform, Celcon, Ramtal, Duracon, Kepital, Polypenco, Tenac and Hostaform.

POM is typically very difficult to bond, with the copolymer typically responding worse to conventional adhesives than the homopolymer.[24] Special processes and treatments have been developed to improve bonding. Typically these processes involve surface etching, flame treatment, using a specific primer/adhesive system, or mechanical abrasion.

Typical etching processes involve chromic acid at elevated temperatures. DuPont uses a patented process for treating acetal homopolymer called satinizing that creates a surface roughness sufficient for micromechanical interlocking. There are also processes involving oxygen plasma and corona discharge.[25][26] In order to get a high bond strength without specialized tools, treatments, or roughening, one can use Loctite 401 prism adhesive combined with Loctite 770 prism primer to get bond strengths of ~1700psi.[24]

Once the surface is prepared, a number of adhesives can be used for bonding. These include epoxies, polyurethanes, and cyanoacrylates. Epoxies have shown 150–1,050 psi (1,000–7,200 kPa)[24] shear strength. Cyanoacrylates are useful for bonding to metal, leather, rubber, cotton, and other plastics.

Solvent welding is typically unsuccessful on acetal polymers, due to the excellent solvent resistance of acetal.[citation needed]

Thermal welding through various methods has been used successfully on both homopolymer and copolymer.[27]
 
I use mostly ebonite and some Alumilite and always epoxy. Epoxy is a mechanical bonding agent, so with all of these liners a strong mechanical bond is important.

The cap liner for both the Apollo and Artemis (Bullseye Turning Supply) are Delrin. They also rely on a mechanical bond.

So to get a good mechanical bond, you need to have a sleeve/insert that provides features for the epoxy to get ahold of. The below picture has the Artemis' Delrin cap liner (top) and one of my Alumilite cap liners (bottom). If you look closely you will see that they are not smooth, but rather have ridges for the epoxy to bind to.

IMG_6468.jpeg
 
I find that Artificial Intelligence (chatgpt) gives pretty good answers, in this case, I have quoted verbatim below:

Delrin (also known as acetal or POM, polyoxymethylene) is notoriously difficult to bond due to its low surface energy and chemical resistance. However, there are specialized methods and adhesives that can work. Here's a breakdown:

🔧 Adhesives That Work (with proper surface prep):

✅ Loctite 401 with Loctite 770 Primer

  • Commonly recommended combination.
  • Loctite 770 primer is critical — it prepares Delrin's surface for bonding.
  • Loctite 401 is a cyanoacrylate (super glue) that bonds well once primed.
  • Use case: Small parts, light load.

✅ 3M Scotch-Weld DP8005 or DP8010

  • These are structural acrylic adhesives designed for low-surface-energy plastics like Delrin and polyethylene.
  • No primer needed.
  • High strength, good impact resistance.
  • Use case: Larger components, more structural needs.

✅ Epoxy with flame or plasma treatment

  • Epoxies normally don't bond well to Delrin — surface modification is required.
  • Flame treatment (quick pass with a propane torch) or plasma etching increases surface energy.
  • Once treated, a good industrial epoxy like West System G/flex may bond.

🚫 Adhesives That Don't Work Well Alone

  • Regular super glue, epoxy, or polyurethane adhesives will typically fail without surface prep or primer.

🔧 Surface Preparation Tips

  1. Clean thoroughly – use isopropyl alcohol to remove grease or mold release.
  2. Roughen surface – light sanding with 180–220 grit improves mechanical grip.
  3. Use primer or treatment – like Loctite 770 or flame treatment.
  4. Clamp – maintain pressure for 24 hours if possible.

Summary

AdhesivePrimer Needed?StrengthNotes
Loctite 401 + 770YesMediumGreat for small parts
3M DP8005 / DP8010NoHighBest option, more expensive
Epoxy + Flame treatmentYesMediumMore effort, variable results
 
its_virgil said:
I use black(mostly) acrylic acetate.
Click to expand...
I have used black Acrylic but find it too brittle under some conditions. I like "slimmer" pens, and are trying to make using an M11 x 1 / M8 x 0.75 combination with a Parker refill. This requires drilling a 15/64" hole for the section. The minor diameter for M8 x 0.75 is 7.188 mm. This means a wall thickness of 0.62 mm. Assuming accurate drilling it can be achieved with Delrin. I haven't tried with Alumilite polyurethane, which might work.
 
ed4copies said:
I find that Artificial Intelligence (chatgpt) gives pretty good answers, in this case, I have quoted verbatim below:

Delrin (also known as acetal or POM, polyoxymethylene) is notoriously difficult to bond due to its low surface energy and chemical resistance. However, there are specialized methods and adhesives that can work. Here's a breakdown:

🔧 Adhesives That Work (with proper surface prep):

✅ Loctite 401 with Loctite 770 Primer

  • Commonly recommended combination.
  • Loctite 770 primer is critical — it prepares Delrin's surface for bonding.
  • Loctite 401 is a cyanoacrylate (super glue) that bonds well once primed.
  • Use case: Small parts, light load.

✅ 3M Scotch-Weld DP8005 or DP8010

  • These are structural acrylic adhesives designed for low-surface-energy plastics like Delrin and polyethylene.
  • No primer needed.
  • High strength, good impact resistance.
  • Use case: Larger components, more structural needs.

✅ Epoxy with flame or plasma treatment

  • Epoxies normally don't bond well to Delrin — surface modification is required.
  • Flame treatment (quick pass with a propane torch) or plasma etching increases surface energy.
  • Once treated, a good industrial epoxy like West System G/flex may bond.

🚫 Adhesives That Don't Work Well Alone

  • Regular super glue, epoxy, or polyurethane adhesives will typically fail without surface prep or primer.

🔧 Surface Preparation Tips

  1. Clean thoroughly – use isopropyl alcohol to remove grease or mold release.
  2. Roughen surface – light sanding with 180–220 grit improves mechanical grip.
  3. Use primer or treatment – like Loctite 770 or flame treatment.
  4. Clamp – maintain pressure for 24 hours if possible.

Summary

AdhesivePrimer Needed?StrengthNotes
Loctite 401 + 770YesMediumGreat for small parts
3M DP8005 / DP8010NoHighBest option, more expensive
Epoxy + Flame treatmentYesMediumMore effort, variable results
Click to expand...
When I decided to try Delrin I didn't appreciate the particular "Rabbit Hole" that I was going down. Now I have plenty to think about! I succeeded in proving what doesn't work!! "Fail to Plan, Plan to Fail". I didn't obtain the Delrin for the discussed purpose. I have been using it to make mandrels for use with wood where brass or aluminum can contaminate the wood. Back to the "drawing board".
 
Graham,

Have you considered drilling the wood for a liner, backfilling the hole with epoxy, let cure appropriately then drill the ID of what would have been your liner?
 
Rick's suggestion works - I think it was Fred Bruche who first posted the method here, it worked for me.

Alternatively, you could do the simple thing - use ebonite or acrylic acetate. Both readily available, take threads well, glue easily, and come in nice colours that can enhance the look of the pen.
 
duncsuss said:
Rick's suggestion works - I think it was Fred Bruche who first posted the method here, it worked for me.

Alternatively, you could do the simple thing - use ebonite or acrylic acetate. Both readily available, take threads well, glue easily, and come in nice colours that can enhance the look of the pen.
Click to expand...
I may go back to using Acrylic. Is there a good source for Ebonite?
 
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