Description
LOCTITE 638 is designed for the bonding of cylindrical fitting parts, particularly with narrow bond gaps approaching 0.25 mm. The product cures when confined in the absence of air between close-fitting metal surfaces. Prevents independent loosening and leaks due to shocks and vibrations.
- Volume: 50ml bottle (Loctite no. 1803365)
- Also available in: 10ml bottle, 250ml bottle
Application
- It not only works on active metals but also on passive substrates, exhibiting robust cure performance.
- The product offers high-temperature performance and good oil tolerance, and tolerates minor surface contaminants.
Characteristics
- High temperature resistance
- Tolerates minor contaminants, including industrial oils
- High strength on all metals, including passive substrates (e.g. stainless steel)
- Ideal for shafts, gears, pulleys and similar cylindrical parts
- Fixture Time: 4 min
Certification
- DVGW Approval (EN 751-1): NG-5146AR0619
- WRAS Approval (BS 6920): 0511518
Technical Information
| Agency Approvals / Specifications | DVGW (EN 751-1): NG-5146AR0619, NSF P1 Reg No: 123010, WRAS (BS 6920): 0511518 |
| Color | Green |
| Diametrical Clearance (Maximum) | 0.25 mm |
| Fixture Time | 4 min. |
| Fixture Time Temperature | 39 °F |
| Full Cure Temperature | 77 °F |
| Gap Fill | 0.01 in. |
| Shear Strength Unit, Steel | psi |
| Shear Strength, Steel | 4500 |
| Specific Gravity | 1.09 g/l |
| Specific Gravity Temperature | 25 °C |
| Substrates | Metal: Steel |
| Temperature | -55.0 – 180.0 °C |
| Viscosity | 2500 mPa.s (cP) Brookfield |
| Viscosity Temperature | 77 °F |
Hazard Information (CLP)

Signal word: Danger
Hazard Statements (H-phrases)
- H315: Causes skin irritation.
- H317: May cause an allergic skin reaction.
- H318: Causes serious eye damage.
- H335: May cause respiratory irritation.
- H412: Harmful to aquatic life with long lasting effects.
Precautionary Statements (P-phrases)
Prevention:
- P273: Avoid release to the environment.
- P261: Avoid breathing vapors.
- P280: Wear protective gloves/eye protection.
Response:
- P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P302+P352: IF ON SKIN: Wash with plenty of soap and water.
- P333+P313: If skin irritation or rash occurs: Get medical advice/attention.
For Consumer Use:
- P101: If medical advice is needed, have product container or label at hand.
- P102: Keep out of reach of children.
- P501: Dispose of contents/container in accordance with national regulation.
Additional Information
No additional hazards if used properly.
Henkel AG & Co. KGaA, Henkelstr. 67, 40589 Düsseldorf, GERMANY, +49 211 7970, [email protected], www.henkel.com






Sophia D. –
The quality surprised me in a good way. A friend recommended it; I’m very happy with the purchase. Super fast delivery, thank you. Better than anything I’ve tried before.
joseph88 –
Simply excellent. Excellent service. Very fast shipping.
klara_s –
I’ve been using it for 2 weeks and I already see results! This solved my problem completely!
hazel88 –
Packaging slightly damaged, but the product is excellent.
ellie.love –
Easy to use, without making a mess.